Overclock.net › Forums › Intel › Intel CPUs › Need some help understanding LLC and offset OCing
New Posts  All Forums:Forum Nav:

Need some help understanding LLC and offset OCing - Page 8

post #71 of 93
Quote:
Originally Posted by tinate View Post

You've seen it on an oscilloscope? That doesn't really make sense to me.

Not personally (the only scope I've got is crap), but other people certainly have.
Quote:
Originally Posted by opt33 View Post

I did testing with couple 1366 cpus, and whatever vcore at load I needed to be stable, it was exactly same with LLC on or LLC off.

I've consistently seen the opposite, across several CPUs (multiple 920s, a 950, a Xeon W3540, and a 970) and several motherboards (ASUS P6TD Deluxe, ASRock X58 extreme, three Gigabyte EA-X58-UD3Rs, and a X58A-UD5). I'm also speaking of long testing runs (24-48+ hours).

My UD5 is the first board I've had where it was even really that close, and I recently turned off LLC after discovering it saved me about 3-5C under load. And that was going from the level 1/moderate setting to off. Level 2/high had serious idle/low load stability issues with similar load voltages to the other settings.
Quote:
Originally Posted by opt33 View Post

Swiftech has done some testing with oscilloscope and multimeter, and felt most stable were LLC settings that maintained similar idle/load vcore, that was done a while back.
http://www.xtremesystems.org/forums/showthread.php?272963-Gigabyte-Z68X-UD4-B3-Voltage-Review&p=4898004&viewfull=1#post4898004

These tests are meaningless (for the purposes of this discussion) for a number of reasons:

1. The oscilloscope used is a Hung Chang 3502C ( http://www.electro-tech-online.com/custompdfs/2009/06/Man_P3502C.pdf ). This is only a 20MHz scope, which is of woefully insufficient bandwidth. Intel specifies a 100MHz scope (page 96, 98 : http://www.intel.com/content/www/us/en/processors/core/2nd-gen-core-family-mobile-vol-1-datasheet.html ). A scope of lesser frequency probably cannot reliably catch transients of the duration we are looking for.

2. There are no scope shots comparing LLC off to the LLC level used, so even if it was an acceptable scope, we'd have nothing to really compare the results to.

3. This is an i7 2600k on a very recent board with a 24-phase VRM. The VRM hardware is total overkill relative to the current the CPU could draw, so isn't going to be a good comparison to any board with a worse VRM or a higher current CPU. That said, the OPs board is equally over-capable relative to a 3770k.
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
post #72 of 93
If I had your experience, I would not use LLC either. However, my experience has been exact opposite, no difference in vcore needed, stability, and since same vcore, no difference in temps, hence I use it.

And I have never seen any oscilloscope proof one way or the other that LLC increases magnitude of overshoots...would have to see video proof before I would believe it.

Though after hearing your experience, I will double check LLC on vs off on my current GB ud5 z77 when I get back home next week..
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
post #73 of 93
Quote:
Originally Posted by opt33 View Post

And I have never seen any oscilloscope proof one way or the other that LLC increases magnitude of overshoots...would have to see video proof before I would believe it.

I'm having trouble find any scope shots of anyone using anything anywhere near specification. I know they exist but finding them among piles of people using inadequate scopes is going to take some doing.

Still, I'm puzzled as to why it would be surprising if a feature (LLC) that removes/limits the feature (vdroop) that is meant to mitigate overshoots had the effect of increasing overshoot.

Again, I wouldn't be entirely surprised if a high-end VRM kept overshoot within spec even at a below Intel spec load line. However, given that the XS link above shows ~10-15mv ripple at a fairly constant load, with a low bandwidth scope, in very low ambients (seriously, 12.4C!?) with a CPU that is only pulling a small fraction of the current the board's VRMs are rated for, I also would not be remotely surprised if specified overshoot was exceeded during shifting loads, under more realistic conditions (those VRMs are going to be 30-40C hotter in a closed case at moderate-high room temperatures), when measured with a higher bandwidth scope.

Definitely worth more testing.

Anyone have a 100MHz+ scope with logging I can borrow?
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
post #74 of 93
Quote:
Originally Posted by Blameless View Post

I'm having trouble find any scope shots of anyone using anything anywhere near specification. I know they exist but finding them among piles of people using inadequate scopes is going to take some doing.
Still, I'm puzzled as to why it would be surprising if a feature (LLC) that removes/limits the feature (vdroop) that is meant to mitigate overshoots had the effect of increasing overshoot.
Again, I wouldn't be entirely surprised if a high-end VRM kept overshoot within spec even at a below Intel spec load line. However, given that the XS link above shows ~10-15mv ripple at a fairly constant load, with a low bandwidth scope, in very low ambients (seriously, 12.4C!?) with a CPU that is only pulling a small fraction of the current the board's VRMs are rated for, I also would not be remotely surprised if specified overshoot was exceeded during shifting loads, under more realistic conditions (those VRMs are going to be 30-40C hotter in a closed case at moderate-high room temperatures), when measured with a higher bandwidth scope.
Definitely worth more testing.
Anyone have a 100MHz+ scope with logging I can borrow?

vrm circuity limits overshoots. vdrop/vdroop just lowers vcore by the same amount as overshoot, so overshoot that still occurs doesnt go past bios setting.

LLC off, bios setting = max overshoot. 1.4 bios setting, 1.34cpuz load, so overshoots may be .06v.

LLC on, bios setting no longer = max overshoot. 1.34 bios = 1.34 cpuz load, overshoots same to .06, given same vrm circuitry.

Until I see scope irrefutable proof otherwise. vdrop/vdroop does not prevent overshoots or lower them, it just drops vcore so overshoot doesnt go over bios setting.

You could design a system to nearly eradicate overshoots, instead of designing a system to just "compensate" for them, but no one would buy such an expensive mobo.
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
post #75 of 93
Thread Starter 
Ok, I seem to be stable at this point, but what does the error on Worker #4 mean?

338
post #76 of 93
Quote:
Originally Posted by opt33 View Post

I did testing with couple 1366 cpus, and whatever vcore at load I needed to be stable, it was exactly same with LLC on or LLC off. If I needed 1.34v for 4.4, I could get their using 1.44 bios with LLC off, or 1.38 bios with LLC on, both were stable, and lowering vcore on either was unstable.
And for 4.7ghz on Ivy, I have run prime with both LLC on turbo and on high, and both ways need same 1.308 vcore at load cpuz.

So far, I'm finding the same thing with a P8Z77-V and 3570k. Comparing 25% and 75%, I get the same load volts for stability, with same temps.

Raja@Asus posted a guide (written by Asus?) that recommends 50% LLC. From page 13 of the pdf:
"For 24/7 use a setting of 50% is considered optimal, providing the best balance between set and load voltage in a manner that compliments the VRM for all loading conditions. Some users prefer using higher values, although this will impact overshoot to a small degree."

For my board, 75% LLC gives the most stable voltage and most straightforward OC (manual V). 50% gives .02-.03 Vdroop in the first part of Prime95, but I get another ~0.01 step of Vdroop about 15 minutes in (wall watts go up then, too), which sometimes causes an error if it's already at the minimum V for stability. 75% gives a 0.01 bump which is very stable.

I've seen statements like "Vdroop is good since it reduces temps when the processor is under heaviest loads." I assume these are referring to the case where Vcore is well above the minimum V for stability? For OCing at or slightly above the minimum stable Vload, I don't see how Vdroop could be good if it then causes an error or crash. For offset V with current BIOS controls, I can certainly see how Vdroop is a useful tool, as it's the only way to adjust the shape of the V(VID) curve. But as mentioned before, it seems far more logical for the BIOS to provide 2 Voffset controls: 1 for idle, 1 for load, and interpolate on top of VID.
Workstation
(9 items)
 
  
CPUMotherboardGraphicsRAM
i7 920, 4.0GHz, 1.21V Asus P6X58D Premium EVGA 9500 GT G Skill 12GB  
Hard DriveHard DriveCoolingOS
WD Patriot Pyro SE 60GB Xigmatek SD1283 DK Win 7 64 bit 
Case
Antec 300 
  hide details  
Reply
Workstation
(9 items)
 
  
CPUMotherboardGraphicsRAM
i7 920, 4.0GHz, 1.21V Asus P6X58D Premium EVGA 9500 GT G Skill 12GB  
Hard DriveHard DriveCoolingOS
WD Patriot Pyro SE 60GB Xigmatek SD1283 DK Win 7 64 bit 
Case
Antec 300 
  hide details  
Reply
post #77 of 93
Quote:
Originally Posted by opt33 View Post

vrm circuity limits overshoots. vdrop/vdroop just lowers vcore by the same amount as overshoot, so overshoot that still occurs doesnt go past bios setting.
LLC off, bios setting = max overshoot. 1.4 bios setting, 1.34cpuz load, so overshoots may be .06v.
LLC on, bios setting no longer = max overshoot. 1.34 bios = 1.34 cpuz load, overshoots same to .06, given same vrm circuitry.
Until I see scope irrefutable proof otherwise. vdrop/vdroop does not prevent overshoots or lower them, it just drops vcore so overshoot doesnt go over bios setting.

Voffset/vdroop also allows full load voltage to settle closer to the maximum undershoot voltage. No VRM responds instantly to changing load demands; there is always some delay.

Without LLC voltage dips, then the VRM responds by lowering voltage in accordance with the default load-line, resulting in a much smaller rebound. With higher levels of LLC, the same dip occurs, but voltage is pushed backup higher. If the minimum voltage achieved during that dip isn't enough to cause instability, load voltage is likely to settle closer to the minimum required when LLC is left disabled.

Even if modern, high-end VRMs are good enough to mitigate most of this discrepancy, LLC still does nothing except conceal the maximum voltage delivered to your CPU. So, best case scenario, LLC doesn't hurt, but it doesn't really help anything either; it just conceals voltage spikes from the user. Worst case scenario means you need more full load voltage to remain stable.
Quote:
Originally Posted by Nihilo View Post

Ok, I seem to be stable at this point, but what does the error on Worker #4 mean?

It means you aren't stable.
Quote:
Originally Posted by david82282 View Post

I've seen statements like "Vdroop is good since it reduces temps when the processor is under heaviest loads." I assume these are referring to the case where Vcore is well above the minimum V for stability?

You assume incorrectly.

The minimum voltage dipped to with LLC off (relative to higher levels of LLC) is typically much closer to the full load voltage it settles at.

Check out pages 5 and 6 of this article for a more detailed explanation of what's happening: http://www.anandtech.com/show/2404/5
Edited by Blameless - 5/12/12 at 6:14pm
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
post #78 of 93
You view LLC as unnecessary. I view vdrop/vdroop as unnecessary when overclocking, since overshoots are going to occur LLC on or off, since same vrm circuitry and same load voltage. Just with LLC off, you know overshoots dont exceed bios setting, which I could care less about when overclocking.

You say LLC is hiding spikes, I dont think of it like that (even though i understand your point). I think of it as vdrop/vdroop sets idle vcore unnecessarily high, so voltage can drop prior to load and overshoots not exceed bios setting.

In reality neither is better or worse, just personal preference. And my personal preference is LLC on.
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
My System
(15 items)
 
  
CPUMotherboardGraphicsRAM
6900K 4.4ghz  MSI X99A Krait Titan XP Gskill 32GB 3200 C14 
Hard DriveHard DriveCoolingOS
Samsung 960 Pro 1TB OS Samsung 850 pro 1TB games D5, XT45 280 rad, Nemesis 280 rad,  Windows 10 64bit 
MonitorPowerCase
Acer Predator XB271HU 144hz Seasonic Prime Titanium 850 Fractal Design R5 
  hide details  
Reply
post #79 of 93
Excellent article -- thanks. It's a pretty interesting controls problem. So, to paraphrase back to see if I understand it: a higher idle V that droops under load is helpful because the VRMs undershoot to a higher minimum V, which helps stability at that instant of undershoot. Once passed that instant, the Vload can then settle to a lower value compared to no Vdroop. Or casually: having Vidle higher than Vload provides a bit of reserve energy (in the capacitors) that is tapped the instant load is turned on -- before the VRMs can respond -- and so the ensuing undershoot is less. ...

Page 51 of this Intel doc has some scope pics of the undershoot and overshoot for a 1366. I couldn't find the version for the 1155 socket, though.

Some details I'm still confused about--
- If idle is at 1600 MHz and load is at 4500 MHz, how does the idle-load transition work if the Voffset method is used? Maybe in this order (?) -- increase Vcc to VID(4500), then increase Ratio for 4500, then load cpu? So if using Offsets, even though Vidle is below 1.0V, the benefits of Vdroop can still be realized, albeit with a little delay to complete the steps?
- How much does digital control of the VRMs change the initial undershoot response? I wonder: if we know a load is turning on and the caps are about to be discharged, could a coordinated current increase be programed to occur simultaneously with the load, to keep the V from undershooting (as much)?
Workstation
(9 items)
 
  
CPUMotherboardGraphicsRAM
i7 920, 4.0GHz, 1.21V Asus P6X58D Premium EVGA 9500 GT G Skill 12GB  
Hard DriveHard DriveCoolingOS
WD Patriot Pyro SE 60GB Xigmatek SD1283 DK Win 7 64 bit 
Case
Antec 300 
  hide details  
Reply
Workstation
(9 items)
 
  
CPUMotherboardGraphicsRAM
i7 920, 4.0GHz, 1.21V Asus P6X58D Premium EVGA 9500 GT G Skill 12GB  
Hard DriveHard DriveCoolingOS
WD Patriot Pyro SE 60GB Xigmatek SD1283 DK Win 7 64 bit 
Case
Antec 300 
  hide details  
Reply
post #80 of 93
Quote:
Originally Posted by opt33 View Post

In reality neither is better or worse, just personal preference.

This isn't reality for every setup. It's fairly clear, that at least in some cases, removing vdroop results in the need for a higher load voltage for the minimum undershoot to be the same.

If this isn't the case with your setup, then yes, it becomes a matter of preference.

The difference for my primary system is large enough for the minimum stable load voltage (and perhaps VRM workload) to be reduced enough (probably only handful of mV, but enough) when LLC is disabled that I reliably reduce CPU temperature by 3-5C and CPU power consumption by a good 10-15w.
Quote:
Originally Posted by david82282 View Post

- If idle is at 1600 MHz and load is at 4500 MHz, how does the idle-load transition work if the Voffset method is used? Maybe in this order (?) -- increase Vcc to VID(4500), then increase Ratio for 4500, then load cpu? So if using Offsets, even though Vidle is below 1.0V, the benefits of Vdroop can still be realized, albeit with a little delay to complete the steps?
- How much does digital control of the VRMs change the initial undershoot response? I wonder: if we know a load is turning on and the caps are about to be discharged, could a coordinated current increase be programed to occur simultaneously with the load, to keep the V from undershooting (as much)?

I suspect these factors would vary by VRM components and firmware implementations. No way to really know for sure without direct measurements.
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
Primary
(15 items)
 
Secondary
(13 items)
 
In progress
(10 items)
 
CPUMotherboardGraphicsRAM
5820K @ 4.2/3.5GHz core/uncore, 1.175/1.15v Gigabyte X99 SOC Champion (F22n) Gigabyte AORUS GTX 1080 Ti (F3P) @ 2025/1485, 1... 4x4GiB Crucial @ 2667, 12-12-12-28-T1, 1.34v 
Hard DriveHard DriveHard DriveCooling
Plextor M6e 128GB (fw 1.06) M.2 (PCI-E 2.0 2x) 2x Crucial M4 256GB 4x WD Scorpio Black 500GB Noctua NH-D15 
OSMonitorKeyboardPower
Windows 7 Professional x64 SP1 BenQ BL3200PT Filco Majestouch Tenkeyless (MX Brown) Corsair RM1000x 
CaseMouseAudio
Fractal Design Define R4 Logitech G402 Realtek ALC1150 + M-Audio AV40 
CPUMotherboardGraphicsRAM
X5670 @ 4.4/3.2GHz core/uncore, 1.36 vcore, 1.2... Gigabyte X58A-UD5 r2.0 w/FF3mod10 BIOS Sapphire Fury Nitro OC+ @ 1053/500, 1.225vGPU/1... 2x Samsung MV-3V4G3D/US @ 2000, 10-11-11-30-T1,... 
RAMHard DriveHard DriveHard Drive
1x Crucial BLT4G3D1608ET3LX0 @ 2000, 10-11-11-3... OCZ (Toshiba) Trion 150 120GB Hyundai Sapphire 120GB 3x Hitachi Deskstar 7k1000.C 1TB 
CoolingOSPowerCase
Noctua NH-D14 Windows 7 Pro x64 SP1 Antec TP-750 Fractal Design R5 
Audio
ASUS Xonar DS 
CPUMotherboardGraphicsRAM
i7-6800K @ 4.3/3.5GHz core/uncore, 1.36/1.2v ASRock X99 OC Formula (P3.10) GTX 780 (temporary) 4x4GiB Crucial DDR4-2400 @ 11-13-12-28-T2, 1.33v 
Hard DriveHard DriveCoolingOS
Intel 600p 256GB NVMe 2x HGST Travelstar 7k1000 1TB Corsair H55 (temporary) Windows Server 2016 Datacenter 
PowerCase
Seasonic SS-860XP2 Corsair Carbide Air 540 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Intel CPUs
Overclock.net › Forums › Intel › Intel CPUs › Need some help understanding LLC and offset OCing