Overclock.net › Forums › AMD › AMD CPUs › NB-CPU voltage and heat generation
New Posts  All Forums:Forum Nav:

NB-CPU voltage and heat generation

post #1 of 12
Thread Starter 
i'm running with a 965 BE@3.95 ghz. checking in on the 9xx club thread's overclocks, i've come to the conclusion that the vast majority of overclockers that break 4.0ghz have CPU-NB voltage at 1.2V+. i'm a bit foggy on what specifically the NB-CPU voltage helps, stability wise, but i think i've read in the past it was CPU.

my CPU voltage is a hair below 1.48, and CPU-NB voltage is at 1.15 (motherboard is ASUS m4a89td). i'm at the max clock i could hammer out of my setup with18x 219 FSB. unfortunately, i've become thermally limited at this point, despite having huge airflow through a correctly installed and thermal pasted CNPS12X (my last run of linx finished at 60.) however, when i even nose my CPU-NB voltage up to 1.2, linx STARTS at 60C! i ran some experiments at stock speed where i knew it would be stable, and i've determined that the heat contribution to the chip per volt of the CPU-NB voltage is 25-50% more than the heat contribution of the CPU voltage itself.

which leads me to my questions, finally. where is the CPU-NB voltage applied, and why does it get the chip that much hotter than CPU voltage? why are so many others able to accomplish the same CPU voltage and a much higher CPU-NB voltage than me without starting fires? if there's a defect, what is it? i'm at a loss mad.gif
post #2 of 12
CPU-NB voltage is applied to the CPU, but not the actual core. It helps out with overclocking the NB frequency (speed of the CPU's memory controller and L3 cache) and running high memory frequency. So basically it's applied to the CPU's memory controller (and possibly L3 cache, although not 100% sure).

This guide from AMD is pretty nifty smile.gif
FreeNAS
(9 items)
 
Beast
(14 items)
 
Alura :)
(11 items)
 
CPUMotherboardGraphicsRAM
Intel Xeon E3-1245 v5 SuperMicro X11SSM-F-O C236 Integrated 2 x 16GB Kingston ValueRAM ECC KVR21E15D8/16 
Hard DriveCoolingOSPower
5 x 8TB Seagate IronWolf Pro in ZF2 Array CoolerMaster Hyper 212 Evo FreeNAS 11 EVGA SuperNOVA G2 550W Gold 
Case
Fractal Design Node 804 
CPUMotherboardGraphicsRAM
i7 4790k Asus Z97 Pro WIFI-AC Sapphire Nitro Radeon R9 Fury Tri-X OC+  G.Skill 4 x 8GB F3-2133C9D-16GXH 
Hard DriveOptical DriveCoolingOS
2 x Intel 730 480GB SSD in RAID 0 Asus DRW-24B1ST/BLK/B/AS Noctua NH-D15 Winblows 10 Pro x64 
MonitorKeyboardPowerCase
Pixio PX277 Logitech G510 Seasonic SS-660XP2 Fractal Design R4 Blackout 
MouseMouse Pad
Logitech G500 Xtrac Ripper 
CPUMotherboardGraphicsRAM
i5 2500k Asus P8Z68-V Pro MSI R7970 Lightning BE 2 x 4GB G.Skill Ripjaws 2133mhz 
Hard DriveOptical DriveCoolingOS
Mushkin Enhanced Chronos 240GB and WD Black 1TB Asus DRW-24B1ST Cooler Master Hyper 212 EVO Windows 7 Ultimate x64 
MonitorPowerCase
Hannspree 24 inch Thermaltake Tough Power TP-750P 750W Gold Cooler Master HAF 932 
  hide details  
Reply
FreeNAS
(9 items)
 
Beast
(14 items)
 
Alura :)
(11 items)
 
CPUMotherboardGraphicsRAM
Intel Xeon E3-1245 v5 SuperMicro X11SSM-F-O C236 Integrated 2 x 16GB Kingston ValueRAM ECC KVR21E15D8/16 
Hard DriveCoolingOSPower
5 x 8TB Seagate IronWolf Pro in ZF2 Array CoolerMaster Hyper 212 Evo FreeNAS 11 EVGA SuperNOVA G2 550W Gold 
Case
Fractal Design Node 804 
CPUMotherboardGraphicsRAM
i7 4790k Asus Z97 Pro WIFI-AC Sapphire Nitro Radeon R9 Fury Tri-X OC+  G.Skill 4 x 8GB F3-2133C9D-16GXH 
Hard DriveOptical DriveCoolingOS
2 x Intel 730 480GB SSD in RAID 0 Asus DRW-24B1ST/BLK/B/AS Noctua NH-D15 Winblows 10 Pro x64 
MonitorKeyboardPowerCase
Pixio PX277 Logitech G510 Seasonic SS-660XP2 Fractal Design R4 Blackout 
MouseMouse Pad
Logitech G500 Xtrac Ripper 
CPUMotherboardGraphicsRAM
i5 2500k Asus P8Z68-V Pro MSI R7970 Lightning BE 2 x 4GB G.Skill Ripjaws 2133mhz 
Hard DriveOptical DriveCoolingOS
Mushkin Enhanced Chronos 240GB and WD Black 1TB Asus DRW-24B1ST Cooler Master Hyper 212 EVO Windows 7 Ultimate x64 
MonitorPowerCase
Hannspree 24 inch Thermaltake Tough Power TP-750P 750W Gold Cooler Master HAF 932 
  hide details  
Reply
post #3 of 12
Quote:
Originally Posted by blode View Post

i'm running with a 965 BE@3.95 ghz. checking in on the 9xx club thread's overclocks, i've come to the conclusion that the vast majority of overclockers that break 4.0ghz have CPU-NB voltage at 1.2V+. i'm a bit foggy on what specifically the NB-CPU voltage helps, stability wise, but i think i've read in the past it was CPU.
my CPU voltage is a hair below 1.48, and CPU-NB voltage is at 1.15 (motherboard is ASUS m4a89td). i'm at the max clock i could hammer out of my setup with18x 219 FSB. unfortunately, i've become thermally limited at this point, despite having huge airflow through a correctly installed and thermal pasted CNPS12X (my last run of linx finished at 60.) however, when i even nose my CPU-NB voltage up to 1.2, linx STARTS at 60C! i ran some experiments at stock speed where i knew it would be stable, and i've determined that the heat contribution to the chip per volt of the CPU-NB voltage is 25-50% more than the heat contribution of the CPU voltage itself.
which leads me to my questions, finally. where is the CPU-NB voltage applied, and why does it get the chip that much hotter than CPU voltage? why are so many others able to accomplish the same CPU voltage and a much higher CPU-NB voltage than me without starting fires? if there's a defect, what is it? i'm at a loss mad.gif

For your question : The CPU-NB Voltage is directly applied to the CPU itself as its giving the volts to the integrated memory controller confined in the CPU. In my case i have the CPU-NB @ 1.2875 V for 2850MHz and never it felt a huge increase in Temp while stress testing or what ever. I think you need to check on that CPU-cooler again for a re-seat or may be you have a 160W TDP 965 C2 Processor ? which were power hunger ?. Can you post a CPU-Z screen shot of the CPU & Memory tabs ??!
    
CPUMotherboardGraphicsRAM
AMD® Phenom-II x4 955 BE - Lapped | 4.14 GHz Asus M4A79T-Deluxe U3S6 [ 790FX | 10 Phase ] Galaxy GTX 470 [ Core=777 | Mem=1800 ] 8GB G.Skill Ripjaws DDR3 1700 MHz | NB=2800 MHz 
Hard DriveOptical DriveCoolingCooling
OCZ Vertex-4 128 GB SSD + Hitachi 320G HDD + WD... LG-DVD±RAM | P-ATA CPU : T.R.U.E 120 Rev.C [ Lapped ] + Scythe Ult... GPU : Arctic Accelero XTREME Plus + VR003 
CoolingOSMonitorKeyboard
Fans : 5 x Xigma 120mm | X-Silent 140mm | CM 200mm Win 8 Pro-MC - 64bit SAMSUNG SA350 24" LED [ 1080p ] Microsoft SIdeWinder x6 Gaming Keyboard 
PowerCaseMouseMouse Pad
SeaSonic ® S12D-850 Watts [80+ Silver | DC-to-DC] Cooler Master™ - HAF 922 [ Xtreme Modded ] Microsoft Optical Standard ednet 
AudioAudioAudioOther
SC: Auzen X-Fi™ Prelude + LME49710HA Op-amp SP: Logitech™ Z-5500 Digital 5.1 [ Modded ] FiiO™ E5 Head-Phone Amp + SoundMagic MP-21 in-ear TIM : Cool-Laboratory Liquid Ultra & Tuniq-TX 4 
OtherOtherOther
Surge Protector : Huntkey UPS : Generic 1000 VA Flash Drives : 2 x 4-GiG's Stick 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
AMD® Phenom-II x4 955 BE - Lapped | 4.14 GHz Asus M4A79T-Deluxe U3S6 [ 790FX | 10 Phase ] Galaxy GTX 470 [ Core=777 | Mem=1800 ] 8GB G.Skill Ripjaws DDR3 1700 MHz | NB=2800 MHz 
Hard DriveOptical DriveCoolingCooling
OCZ Vertex-4 128 GB SSD + Hitachi 320G HDD + WD... LG-DVD±RAM | P-ATA CPU : T.R.U.E 120 Rev.C [ Lapped ] + Scythe Ult... GPU : Arctic Accelero XTREME Plus + VR003 
CoolingOSMonitorKeyboard
Fans : 5 x Xigma 120mm | X-Silent 140mm | CM 200mm Win 8 Pro-MC - 64bit SAMSUNG SA350 24" LED [ 1080p ] Microsoft SIdeWinder x6 Gaming Keyboard 
PowerCaseMouseMouse Pad
SeaSonic ® S12D-850 Watts [80+ Silver | DC-to-DC] Cooler Master™ - HAF 922 [ Xtreme Modded ] Microsoft Optical Standard ednet 
AudioAudioAudioOther
SC: Auzen X-Fi™ Prelude + LME49710HA Op-amp SP: Logitech™ Z-5500 Digital 5.1 [ Modded ] FiiO™ E5 Head-Phone Amp + SoundMagic MP-21 in-ear TIM : Cool-Laboratory Liquid Ultra & Tuniq-TX 4 
OtherOtherOther
Surge Protector : Huntkey UPS : Generic 1000 VA Flash Drives : 2 x 4-GiG's Stick 
  hide details  
Reply
post #4 of 12
Quote:
Originally Posted by blode View Post

i'm running with a 965 BE@3.95 ghz. checking in on the 9xx club thread's overclocks, i've come to the conclusion that the vast majority of overclockers that break 4.0ghz have CPU-NB voltage at 1.2V+. i'm a bit foggy on what specifically the NB-CPU voltage helps, stability wise, but i think i've read in the past it was CPU.
my CPU voltage is a hair below 1.48, and CPU-NB voltage is at 1.15 (motherboard is ASUS m4a89td). i'm at the max clock i could hammer out of my setup with18x 219 FSB. unfortunately, i've become thermally limited at this point, despite having huge airflow through a correctly installed and thermal pasted CNPS12X (my last run of linx finished at 60.) however, when i even nose my CPU-NB voltage up to 1.2, linx STARTS at 60C! i ran some experiments at stock speed where i knew it would be stable, and i've determined that the heat contribution to the chip per volt of the CPU-NB voltage is 25-50% more than the heat contribution of the CPU voltage itself.
which leads me to my questions, finally. where is the CPU-NB voltage applied, and why does it get the chip that much hotter than CPU voltage? why are so many others able to accomplish the same CPU voltage and a much higher CPU-NB voltage than me without starting fires? if there's a defect, what is it? i'm at a loss mad.gif

I've never seen a system where raising it was necessary for a processor overclock; only higher FSBs (obviously, since the NB/HTL might be overclocked as well) or when directly increasing the NB/HTL via their respective multipliers.

In such cases where increasing the voltage is not necessary, it is not only increasing the temp on the processor die (socket, not core temp), but increasing the stress put on the VRMs.

Even on my crap Gigabyte old mobo running 1200 ddr2, no voltage increase is necessary, so I'm not sure when it would be.

Also, what kind of cooling are you using? The heat contribution should be like 1-2C per .050V added, least it is on my 960T; Of course, if you have bad cooling it would be higher.
Edited by ozzy983 - 2/6/12 at 7:30am
Primary
(11 items)
 
  
Reply
Primary
(11 items)
 
  
Reply
post #5 of 12
Thread Starter 
it's just on air but with a Zalman CNPS12X . i'm confident that it's seated correctly and the TIM is on there correctly.
i have RB-C3 revision, so i know it's the less volt hungry of the two. my NB is only at 2415 and if i get to about 2550 it's unstable, with RAM at ~1450hz frown.gif
post #6 of 12
Your ram might be the issue too; I'm assuming it's only rated @ 1333. Might want to look into some nice 1666mhz to give you the extra room to play with the bus a bit more.
Primary
(11 items)
 
  
Reply
Primary
(11 items)
 
  
Reply
post #7 of 12
Bah,your doing something wrong. No way your CPU/NB @ 1.2v is causing you heat problems.What are your ambient temps and idle temps with stock settings?
Amelia
(13 items)
 
Professional
(13 items)
 
RCPC#1
(17 items)
 
CPUMotherboardGraphicsRAM
Phenom II X6 1100t MSI 890FX GD65 MSI Radeon HD5670 GSkill RipjawsX DDR3 PC3 12800 2x4GB CL8 
Hard DriveOptical DriveCoolingOS
WD Black 1TB SATA III Samsung BD Zalman 9900MAX Windows 7 64 Professional 
MonitorKeyboardPowerCase
AOC 22" LED Logitech Kingwin Lazer Platinum 500w Fractal Design R3 
Other
Samsung 470 SSD 128GB 
CPUMotherboardGraphicsRAM
AMD Phenom II X6 960T Asus M4A88T-VEVO Asus Strix R7 370 SuperTalent Perfomance 
RAMHard DriveHard DriveOptical Drive
GSkill Snipers Monster Daytona Seagate Barracuda 500GB 7,200 RPM 16Mb cache Memorex DVD/RW 
CoolingOSMonitorKeyboard
Corsair H60 Windows 8N IBM 9494 19" LCD IBM 
PowerCaseMouseMouse Pad
Corsair GS500 In Win H-Frame Wolfking OCZ Behemoth 
Audio
JBL Creature 
  hide details  
Reply
Amelia
(13 items)
 
Professional
(13 items)
 
RCPC#1
(17 items)
 
CPUMotherboardGraphicsRAM
Phenom II X6 1100t MSI 890FX GD65 MSI Radeon HD5670 GSkill RipjawsX DDR3 PC3 12800 2x4GB CL8 
Hard DriveOptical DriveCoolingOS
WD Black 1TB SATA III Samsung BD Zalman 9900MAX Windows 7 64 Professional 
MonitorKeyboardPowerCase
AOC 22" LED Logitech Kingwin Lazer Platinum 500w Fractal Design R3 
Other
Samsung 470 SSD 128GB 
CPUMotherboardGraphicsRAM
AMD Phenom II X6 960T Asus M4A88T-VEVO Asus Strix R7 370 SuperTalent Perfomance 
RAMHard DriveHard DriveOptical Drive
GSkill Snipers Monster Daytona Seagate Barracuda 500GB 7,200 RPM 16Mb cache Memorex DVD/RW 
CoolingOSMonitorKeyboard
Corsair H60 Windows 8N IBM 9494 19" LCD IBM 
PowerCaseMouseMouse Pad
Corsair GS500 In Win H-Frame Wolfking OCZ Behemoth 
Audio
JBL Creature 
  hide details  
Reply
post #8 of 12
Thread Starter 
Quote:
Originally Posted by Redwoodz View Post

Bah,your doing something wrong. No way your CPU/NB @ 1.2v is causing you heat problems.What are your ambient temps and idle temps with stock settings?

you know, i reverted to stock (or Auto settings for everything, as it were) and at 1.42 volts on the CPU, i was seeing 45 degrees idle with full fans! that's dang high, and i know that when i first put on the paste, i would wake up and see temps of 29-32 with CNQ on, and high power state temps of ~40. however, i didn't really do anything intense for the first few days game-wise or CPU-wise even, and i wonder if the temps went up the second i stopped being concerned about it.

yesterday, i pried the heatsink off and realized i had way too much paste, so i reapplied and reseated and was seeing the same temp of 39-40 and 32 at lower voltage state. after rebooting to my last clock (1.48V high) it was still only ~44, but the second it hit the heavy linX load, it went right to 58-60 range! what the heck? and afterward, it wouldn't go lower than 48 degrees idle

one thing i noticed is that the 2 lb heatsink will twist :/ i've always had this problem even with screws as tight as possible, and i can't conceive of a fix with the way the AMD bracket is attached to the mobo.
is there an air gap or TIM drying up too fast or something? i guess maybe my problem IS as elementary as improperly installed heatsink, even though i followed the dadgum guide. maybe i should poke around and see who else has this cooler on an AMD bracket and ask if they have this issue...
post #9 of 12
Maybe take the Heatsink off, and check for flatness on the plate and the CPU. You may have a defective H.S.

Find a razor blade, Place the sharp side down,and look for light showing between the two from the side. be sure to check both the CPU and the H.S.
Wet Willy
(17 items)
 
Oold man 555
(11 items)
 
 
CPUMotherboardGraphicsRAM
i7 920 @4.217 1.24 v's 24/7 Asus p6t6 ws Revolution (full water blocks) GTX 480 SLI @867-1734 samsung 30nm at 2040mhz. 8-9-9-26 1.54v's 
Hard DriveOptical DriveCoolingCooling
OCZ Agility 3 RAID0 lite on dvd burner Raystorm Danger Den 480 Full copper (paralleled)  
OSMonitorMonitorKeyboard
Dual boot, Windows7 64bit/Linux ubuntu64bit 1hpw2207h1680/1050  Sharp 60" LED 120hz s510 
PowerCaseMouseAudio
Ultra 1600w X4 NZXT, Tempest EVO logitech s510 combo Harmon Kardon AVR245 
CPUMotherboardGraphicsRAM
Phenom II X4 B55 m4n82 deluxe ghetto gtx 460 patriot viper 1066 
Hard DriveOptical DriveCoolingOS
some crap sata dvd thermal take big typhoon windows 7 ultimate  
MonitorPowerCase
hp 2207h ultra lsp 750watt cooler master elite 
  hide details  
Reply
Wet Willy
(17 items)
 
Oold man 555
(11 items)
 
 
CPUMotherboardGraphicsRAM
i7 920 @4.217 1.24 v's 24/7 Asus p6t6 ws Revolution (full water blocks) GTX 480 SLI @867-1734 samsung 30nm at 2040mhz. 8-9-9-26 1.54v's 
Hard DriveOptical DriveCoolingCooling
OCZ Agility 3 RAID0 lite on dvd burner Raystorm Danger Den 480 Full copper (paralleled)  
OSMonitorMonitorKeyboard
Dual boot, Windows7 64bit/Linux ubuntu64bit 1hpw2207h1680/1050  Sharp 60" LED 120hz s510 
PowerCaseMouseAudio
Ultra 1600w X4 NZXT, Tempest EVO logitech s510 combo Harmon Kardon AVR245 
CPUMotherboardGraphicsRAM
Phenom II X4 B55 m4n82 deluxe ghetto gtx 460 patriot viper 1066 
Hard DriveOptical DriveCoolingOS
some crap sata dvd thermal take big typhoon windows 7 ultimate  
MonitorPowerCase
hp 2207h ultra lsp 750watt cooler master elite 
  hide details  
Reply
post #10 of 12
Quote:
Originally Posted by blode View Post

you know, i reverted to stock (or Auto settings for everything, as it were) and at 1.42 volts on the CPU, i was seeing 45 degrees idle with full fans! that's dang high, and i know that when i first put on the paste, i would wake up and see temps of 29-32 with CNQ on, and high power state temps of ~40. however, i didn't really do anything intense for the first few days game-wise or CPU-wise even, and i wonder if the temps went up the second i stopped being concerned about it.
yesterday, i pried the heatsink off and realized i had way too much paste, so i reapplied and reseated and was seeing the same temp of 39-40 and 32 at lower voltage state. after rebooting to my last clock (1.48V high) it was still only ~44, but the second it hit the heavy linX load, it went right to 58-60 range! what the heck? and afterward, it wouldn't go lower than 48 degrees idle
one thing i noticed is that the 2 lb heatsink will twist :/ i've always had this problem even with screws as tight as possible, and i can't conceive of a fix with the way the AMD bracket is attached to the mobo.
is there an air gap or TIM drying up too fast or something? i guess maybe my problem IS as elementary as improperly installed heatsink, even though i followed the dadgum guide. maybe i should poke around and see who else has this cooler on an AMD bracket and ask if they have this issue...

You could try laying the PC on it's side -- will keep the HS on the CPU better if you feel it's pulling away. At least, from a diagnostic standpoint, it might give you something to go on.
Primary
(11 items)
 
  
Reply
Primary
(11 items)
 
  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: AMD CPUs
Overclock.net › Forums › AMD › AMD CPUs › NB-CPU voltage and heat generation