core i7 950 OC problem

[kayawish]

hello....
(my system specs are below in my signature)

Now i dont know that is my i7 950 D0 is bad batch or i am doing something wrong in overclocking.my Overclock is 10 hours prime95 stable @ 3.7GHz and the settings i used in bios are.

23x multiplier
BCLK 161
DRAMFrequency 1614 MHz
UCLK 3227 MHz

8-8-8-21

CPU VTT 1.22
QPI 1.4
Dram volts 1.54

rest of everything is on AUTO and HT is also OFF /Turbo is also OFF
on these settings my i7 950 @ 3.7GHz is stable more then 10 hours in prime95 blend test and NO errors but when i try to overclock my cpu to 4 GHz its even not stable @ 1.33v

the settings i used for OC it to 4 GHz is same as above except Dram is running @ 1750 MHz and even its not stable if i run the ram @ 1450 MHz.even increasing / decresing Multi & Bclk is not stable @ 4ghz on 1.33v.so why my i7 950 requires such a high increase in CPUVTT from 3.7GHz to 4GHz.
3.7GHz stable on 1.22v while for 4GHz it take more then 1.33v.why is this?
__________________
CPU: Intel Core i7 950 @ 3.7GHz w/o HT 1.22v 24/7 * | Cpu Cooler: Thermaright 120 ULTRA Xtreme | Board: ASUS P6t6 WS Revolution | Mem: 6GB DDR3 G.Skills PC3 16000 Running @ 1600 MHz 8-8-8-21 @ 1.54v QPI @ 1.4 | GPU: Nvidia 3 x XFX GTX 260 Core 216 3-WAY SLI @ 700/1250/1431 (Core/Memory/Shader)
| HDD:- 640GB S-ATA Seagate Baracuda 32 Mb Cache 7200 Rpm | Cassing: NZXT Tempest *BIG TOWER*
PSU: Xigmatik NRP 1500 Watts

 

[doz]

Why are you running your ram at 1.54v? Im pretty sure its rated at 1.65v (All the 2000mhz ram I found were atleast rated at that). Have you tried setting it to the default voltage? Just because you underclocked it doesnt mean it will run with less volts.

That COULD be your problem, not saying it is. Id give that a shot first and report back. Also, try lowering your QPI. You shouldnt need near that much and higher QPI's have been known to make it unstable unless its needed. For starters, try setting it at .05v above your vcore.

 

[kayawish]

how can you say that?my ram is GSkils triedent PC3-16000 @ 2000MHz and i am running it @ 1600MHz because my system wont boot when ram is @ 2000MHz even i put QPI to 1.50v.if i lower my QPI to 1.35 then it was even not stable @ 3.7ghz

 

[Daddyjaxx]

Your RAM is rated at 1.65 volts like he says. Running it at that won't hurt anything.

For that speed, I'd start out with:

CPU 1.24
QPI 1.24
DRAM: 1.6-1.64 or 1.66 You can't get exactly 1.65 on most boards. When the memory is at 1.65, never drop QPI below 1.15.

If that's all the overclock you want, keep lower the voltages until it craps out. If it craps out at these voltages, well...up them one at a time.

 

[kayawish]

ya i tried them all i7 950 need more volts then i7 920 may be.i am planning to buy i7 920 D0

 

[doz]

Its not the QPI im saying put at 1.65, its the RAM. Two different voltages. Even though your ram is running lower, it will still likely require the same voltage. DDR3 is different than previous ram.

And, if by chance it doesnt help, lower it later. I dont see why you would mess with it in the first place. You are trying to test stability, but you arent giving it the voltage that its rated for to begin with. Tweak the ram later, get your CPU stable first.

 

[kayawish]

ok ram is on 1.64v now and prime95 blend is curently running i will post again tommarow.2 hours gone no crash or BSOD