Overclock.net › Forums › Components › Memory › Memory timing rules of thumb?
New Posts  All Forums:Forum Nav:

Memory timing rules of thumb?

post #1 of 7
Thread Starter 
I've given up trying to run my memory at 2000mhz on my rig. I went from barely stable (freezes every few hours) to unusable (freezes within minutes of booting) on the same settings... worried I may have degraded my memory controller or sticks in the attempts, the qpi was getting pretty damn high (>1.5v).

Anyway, I'm working instead toward getting the tightest timings possible at 1600mhz, to see what performance I can squeeze out that way. So far I have:

CAS: 6
tRCD: 6
tRP: 6
tRAS: 14
tRC: 20
tRRD: Auto (4)
tWTR: Auto (4)
tWR: 8
tWTP: 19
tWL: 7
tRFC: Auto (60)
tRTP: Auto (4)
tFAW: Auto (16)
Command Rate: Auto (1)
Round Trip Latency: Auto (47)

I've derived some of these timings from formulas I've seen mentioned. I don't know what the technical reason behind them is or how sound they are. The ones I've collected so far, are:

tras = tcl + trcd + 2
trc >= tras + trp
twtr = twl + 4
twl = cas - 1
twtp = twr + twl + 4

Derived from here and here.

I'm wondering if there are any others I can use?
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
post #2 of 7
Thread Starter 
Also are there any voltages that can be raised to improve timings even further?
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
post #3 of 7
Thread Starter 
Seems some of the formulas I've found are just plain wrong. trfc = trc + 4 for example... would set it at nearly half of what auto sets it at, and indeed trying it out my computer's alarm started buzzing to indicate a memory error.

EDIT: Sorry for multiposting, is there a way to merge them?
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
post #4 of 7
TRFC of 60 is pretty low. You will find as you populate more dimms, you will have to increase it significantly. Your timings look great at 1600. I ran my 3x2Gb Trident DDR3 2000 Cas 9 at those same timings as you do now. I think for me, it was the TRFC I played with to get stability. If it is unstable, try bumping it up to 68 (I think that is the next highest... or close to that). 6-6-6-20 1T is great for 1600, and will rival 2000 Cas9 .
My System
(16 items)
 
  
CPUMotherboardGraphicsRAM
6850K ASUS X99-AII eVGA GTX 1060 32Gb Team Vulcan DDR4 3000 Cas 15 
Hard DriveHard DriveHard DriveHard Drive
Samsung 960 EVO NVME Crucial M500 Seagate HDD Samsung F3 
CoolingOSMonitorKeyboard
H100i Windows 10 Pro 64 Samsung KU6300 40" Corsair K70 Vengeance 
PowerCaseMouse
Seasonic Gold 750W Phantek Enthoo Pro M Logitech G9X 
  hide details  
Reply
My System
(16 items)
 
  
CPUMotherboardGraphicsRAM
6850K ASUS X99-AII eVGA GTX 1060 32Gb Team Vulcan DDR4 3000 Cas 15 
Hard DriveHard DriveHard DriveHard Drive
Samsung 960 EVO NVME Crucial M500 Seagate HDD Samsung F3 
CoolingOSMonitorKeyboard
H100i Windows 10 Pro 64 Samsung KU6300 40" Corsair K70 Vengeance 
PowerCaseMouse
Seasonic Gold 750W Phantek Enthoo Pro M Logitech G9X 
  hide details  
Reply
post #5 of 7
Thread Starter 
Well, i've tightened the timings quite a bit since I made the OP. smile.gif And actually lowered the trfc considerably, for negligable improvements in speed. In benchmark terms I get around 28.7 GB/sec now (back when 2000mhz was semi-stable it got me 33 GB/sec, for comparison).

One question :What the heck is tWL? Not even google turns up an answer and I've tried all kinds of queries...
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
post #6 of 7
how to tighten RAM timings:
1)boot into BIOS
2)lower the 4 values..1 at a time..1 notch @ a time..lower,reboot...lower..reboot..until no POST..then raise 1.go to next timing.rinse,repeat..:lachen.gif:
3)tras should generally be the sum of the 3..
4)to improve stability..increase trfc/dram voltage
 
Thuban Powah!
(14 items)
 
 
CPUMotherboardGraphicsRAM
Xeon X5650 Asus P6X58D-E Sapphire HD 7950 G.Skill Trident-X 2600 CL10 
Hard DriveCoolingPowerCase
Samsung 840 pro Bong cooler / RASA waterblock Rosewill Capstone Gold 750 None 
MouseMouse PadAudio
cheap! Newegg box panel ibeats with onboard. 
CPUMotherboardGraphicsRAM
AMD Phenom II X6 1075T w/2 cores locked @ 4.2+ M4a89GTD-Pro XFX Radeon HD 5870 8gb Samsung ddr3 1600 11-11-11-28@ 8-8-8-24 
Hard DriveHard DriveOptical DriveCooling
OCZ Agility2 40gb WD Blue 500GB Lite-On RASA waterblock 
OSMonitorKeyboardPower
Windows & Linux Samsung 1080p 2 ms Dell Thermaltake TR2-800 
CaseMouse
Cooler Master Elite 330 (was) cheap 
  hide details  
Reply
 
Thuban Powah!
(14 items)
 
 
CPUMotherboardGraphicsRAM
Xeon X5650 Asus P6X58D-E Sapphire HD 7950 G.Skill Trident-X 2600 CL10 
Hard DriveCoolingPowerCase
Samsung 840 pro Bong cooler / RASA waterblock Rosewill Capstone Gold 750 None 
MouseMouse PadAudio
cheap! Newegg box panel ibeats with onboard. 
CPUMotherboardGraphicsRAM
AMD Phenom II X6 1075T w/2 cores locked @ 4.2+ M4a89GTD-Pro XFX Radeon HD 5870 8gb Samsung ddr3 1600 11-11-11-28@ 8-8-8-24 
Hard DriveHard DriveOptical DriveCooling
OCZ Agility2 40gb WD Blue 500GB Lite-On RASA waterblock 
OSMonitorKeyboardPower
Windows & Linux Samsung 1080p 2 ms Dell Thermaltake TR2-800 
CaseMouse
Cooler Master Elite 330 (was) cheap 
  hide details  
Reply
post #7 of 7
Thread Starter 
I read on a page that lowering one of the advanced timings causes voltage spikes, but can't find it now... might have been tRRD?

Anyone know if changing tFAW can improve performance? LOwering it doesn't seem to, not sure about raising it.

UPDATE:

I managed to break 29 GB/sec by _raising_ the TRRD (!?). Unfortunately on subsequent reboots it fails to match that result. Could it be that Sisoft Sandra is just a poor inconsistent benchmarker?


Here are my timings now:
CAS:
tRCD: 6
tRP: 5
tRAS: 17
tRC: 22
tRRD: 7
tWT: 4
tWR: 1
tWTP: 11
tWL: 6
tRFC: 45
tRTP: 1
tFAW: 16
Round Trip Latency: 47 (auto)

I'm wondering if fiddling with those dram termination figures could milk anymore performance. Anyone got any other suggestions? Most tutorials emphasise raising clock speed first, but I just want to work the timings as much as I can...

Update:
Managed to drop tWTR to 1 as well, seemed to create a negligable performance increase. Is there anything unusual/dangerous about these timings?
Edited by auricgoldfinger - 12/22/11 at 8:38am
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
Contuter
(14 items)
 
  
CPUMotherboardGraphicsRAM
i7 920 SLBEJ OC'd @ 4.4 ghz Gigabyte GA-EX58-UD3R Rev 1.6 MSI GTX 780 twin frozr Kingston HyperX 2000mhz @ 1600mhz 6-6-6-16 
Hard DriveHard DriveOptical DriveOS
Seagate Barracuda 7200.12 1TB SATA-2 Samsung SSD 840 EVO 120GB Samsung SH-S223B/BEBE 22x DVD±RW SATA Dual Layer Windows 7 Home Premium 64 bit OEM 
MonitorPowerCase
Dell U2410 Cooler Master m700 Real Power Cooler Master Centurion 590 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Memory
Overclock.net › Forums › Components › Memory › Memory timing rules of thumb?