# 4ghz need to stabilize boot



## Aus_Karlos (Mar 10, 2007)

Hey guys just doing a bit of Overclocking on my i7-950.
Im having a problem with the system cold booting, It will either take a while to get to the POST screen or loads Fail-Safe settings then takes me to the BIOS.
On restart (In Windows) it will POST just fine.

Current settings -
Core @ 4.02ghz (174x23)
QPI Link @ 6.7ghz (Auto)
Uncore @ ~3150mhz (x18)
DDR @ 1400mhz (x8)
RAM @ 9-9-9-24 @ 1400mhz

Voltage -
Vcore @ 1.32v
QPI/VTT @ 1.33v
CPU PLL @ 1.86v
IOH Core @ 1.20v
DIMM @ 1.64v
Load-Line Calibration @ Level 1

Once in Windows however the OC is rock solid, i can leave Prime95 running all day and it wont fail. CPU temps dont go over 65c and RAM sits at about 40c, N/B at 40c.
Ive asked around and some people are suggesting its my RAM not able to draw enough voltage at cold boot. But i dont want to take the voltage above specs unless its the cause.


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## Johnny1982 (Oct 15, 2010)

Try lowering your QPI link speed as well as your Ram speed to see if it helps.


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## Aus_Karlos (Mar 10, 2007)

The QPI is the link between the CPU and SouthBridge and many users that OC tend to leave it on auto as the bandwidth will only be utilized when needed. However i might back the Uncore down. Its the link between the CPU and RAM. Ive only seen a few OCers obtaining 3.2ghz while others have it at about 2.8-3ghz.

Someones also suggested that i should connect the extra 4-pin CPU connector. Even though its for Extreme edition CPUs my OC is well above those CPUs power draw.


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## Wrench97 (May 10, 2008)

Definitely use the 8 pin CPU power connector, even on non extreme it evens the load on the CPU power regulation circuits on the board.

What is the uncore voltage set to?


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## Aus_Karlos (Mar 10, 2007)

QPI/VTT @ 1.33v, but i might bump it up some more as i am utilizing all 6 slots.


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## Wrench97 (May 10, 2008)

Usually with 6 sticks it's best to drop the memory speed, testing with 3 sticks will give you a hint if that's the answer, raising the QPI/VTT may help some but I wouldn't go past 1.36v


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## Aus_Karlos (Mar 10, 2007)

I'll back it down to x6 which is about 1050mhz and i'll see if it boots better. If it does i should be able to tighten the timings to decrease latency to combat the frequency loss.


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## Johnny1982 (Oct 15, 2010)

Why did you not connect both 4-pin CPU connectors? I did it on my I3-550, even at stock speed and mine's an entry level CPU compared to yours. I've heard that if your QPI link is too high it can give problems as well.


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## Aus_Karlos (Mar 10, 2007)

Well i dropped it down to x6 and the Ucore x12 in respect and it failed to boot.Running over some OC guides it seems the i7-950 will not boot with an Uncore of x12. :S
I need to keep the Uncore/DRAM ratio 2:1 otherwise it wont boot.

@ Johnny
The QPI link is locked pretty much with the CPU. The only other options are Slow Mode, x35, x44 and x65.
At the moment its on x35 which is what Auto will do aswell. Slow Mode will stick it to 88mhz, lol so thats a no go. So i cant actually back it down.


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