Trying to hit 4ghz stable - i7 920

[Acejam]

Hey guys,

I'm trying to hit a stable 4ghz on my i7 920 build. I'm running the following setup:

i7 920 D0 (MicroCenter batch)
Asus P6T (vanilla)
OCZ Gold 6GB 8-8-8-24
Antec 1200 Case
CoolerMaster V8 HSF

Current settings as follows:
Multi: 21
BCLK: 175
CPU VCore: 1.21875
PLL: Auto
QPI Volt: 1.25
VDimm: 1.64
Ram Timings: 8-8-8-24 (rest are set to auto)
IOH: Auto
ICH: Auto

HyperThreading: On
C1E: Disabled
CPU Spread Spectrum: Disabled
Execute Disable Bit: Disable
Turbo Mode: Disabled
SpeedStep: Disabled
Load Line Calibration: Enabled
(all other settings left on auto)


Currently the machine is running at 3675 mhz and has been Prime95 blend stable for the past 10 hours.

Also, it appears that 1.21875 is my stock VID. I found this by setting everything to auto, and going full load on Prime95, and checking CPU-Z. I then set my CPUVcore to this value and my BCLK to 133, and upped my BCLK by 10, tested, and repeated until 183. 183 appears to cause a BSOD when trying to run Prime95. (occurs about 20-30 seconds into starting a blend test with 8 threads) Therefore, I backed my BCLK back down to 175 (not 173) and so far it appears to be stable.

My question is - what value should I bump next to try and hit 4ghz? If I try bumping CPUV, it looks like that I still receive BSOD's. Should I try bumping QPI next?

Obviously I'm trying to do this with as low voltage as possible. (efficient overclock) I'm not too concerned about my temps at this point in time, but FWIW they are hovering around 65-70 right now. (CoolerMaster V8) I've read that a lot of people with D0's have been able to hit 4ghz with only 1.25 vcore. I followed a number of guides with published settings but didn't have much luck in those configs being stable. (However I could POST and boot into windows ok)

Any advice is greatly appreciated.Thanks in advance!

- Ace

 

[DudeThe]

I have a C0, and rest in my Sig.

Current settings as follows:
Multi: 21
BCLK: 181
CPU VCore: 1.3
PLL: Auto (1.8) Yours seems low.
QPI/DRAM Volt: 1.5
VDimm: 1.64 (Running @ 905MHz with 8-8-8-24 1T)
Ram Timings: 8-8-8-24 1T(Manually adjusted)
IOH: Auto
ICH: Auto

HyperThreading: On

SpeedStep: Enabled (keeps temp low when not needed)

Temps Idle 44-46C, and with OCCT running Max 69-71C.

Rest everything is left as it is.

Hope this helps.

 

[ighardcore]

Increasing QPI really helped me reach a stable OC on my 920, but 1.8 may be a bit too high. I had to up mine to 1.4-1.5 range to start seeing a much more stable system. With 1600 RAM (assuming you are using it), your QPI will need the extra voltage to be stable, at least with my experience. Also make sure your uncore is set to exactly 3200 (with 1600 RAM; set it to double your RAM clock, no more else you may need to play with PLL settings from what I've read/experienced). I would recommend trying 1.35, then 1.4, then 1.45, etc., until it is stable. 1.8V on the QPI is likely too high / unnecessary unless you're really pushing your RAM speeds up. I had problems for the longest time getting my system stable, these tips helped me, hopefully they can help you.

 

[DudeThe]

O had some mistakes in my above post corrected it QPI is 1.5.....