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I7 voltage levels

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June 29, 2009 8:47:15 AM

My system:
1) i7 920 intel processor, D0 Step
2) Gigabyte extreme MB, with the optional NorthBridge heatsink installed.
3) Liquid cooling, CPU only
4) HAF case.

Current Overclocks:
1) CPU 4.0 GHZ
2) Memory: 2000 MHZ at 7-7-7-18 timings
3) QPI 7.2 GT
4) Northbridge 4000 MHZ

My question is whether my voltages are set to dangerous levels or not?
I followed the advice of the gigabyte marketing/tech guy,
and set my voltages for:

(the gigabyte guide: http://images.tweaktown.com/imagebank/Core%20i7%20920%2...(ENG).pdf)

CPU Vcore: 1.40
QPI/VTT Voltage: 1.515
Dram Voltage 1.64 (within 0.5V of Vcore/QPI)

All my other voltages are set at defaults (i think).

My temperatures under load for the CPU is 48 Celsius, under 30+ min
Prime-95 8 thread "Large FTT/torture" test.

I'm new to Overclocking, and don't know if most people try to keep their QPI/VTT
voltage lower due to temperature concerns (which probably aren't an issue for me
given my cooling system), or whether this voltage is too much even with good cooling.

Any thoughts? System seems rocksolid right now, no blue screens, errors,
and cool temps under load.



More about : voltage levels

June 29, 2009 10:02:48 AM

update:

Was able to bring CPU voltage down to 1.35, running torture test now with no errors so far. (1.325 produced errors).

Also brought down QPI/VTT voltage down to 1.435, i tried one step lower but got blue screens or lockups ( i did this before lowering cpu voltage if there's a relation).
The high QPI/VTT was my biggest concern. Cause 1.515 was a lot higher than i saw most Overclockers going. Still wondering if i can bring this down a little more by raising something else.
June 29, 2009 8:21:16 PM

I tend to try to keep my CPU and VTT voltage at the same levels in order to keep heat down. I use 1.30 volts as the high end for my 24/7 overclock of 3.4 GHz on a CO 920.

Are you trying for a max overclock or trying for a 24/7 overclock? If you are going for a max overclock I would set 1.45 as the absolute max with water cooling. If you are going for a 24/7 overclock I would stay at 1.35 as the max. I didn't get a huge benefit by going from 1.30 to 1.35, so I decided to stay at 1.30.

Try putting your voltage at 1.30 for CPU and VTT and playing around with the multiplier and Bclk. You may find a higher Bclck and lower multiplier yield different results. Once you find your max overclock at 1.30 volts switch to 1.325 and start again, then switch to 1.35 and see where things go. Eventually you will see what benefits the higher voltages yield and if they are worth possibly shortening the life of your CPU.

A good tool to use to test is Intel Burn Test (download here: http://downloads.guru3d.com/IntelBurnTest-v2.0-download...). Set it to use as much as memory as possible, using 8 threads, and set it for 10 passes. Generally I find that Burn Test will find errors within 30 minutes that may take 8 or more hours for Prime 95 to find.
Related resources
June 29, 2009 9:10:11 PM

update:

CPU Vcore - 1.375 in bios (but hardware monitor on Easytune6 shows near constant 1.328 volts?)
- Also 1.375 fairly safe? think it falls within intel max. Yes the comp is for 24/7 use, heavy load,
so don't want to push it much.
QPI/VTT voltage - 1.35
- about 1hr into Prime 95 torture test, so far so good....

CPU - at 4.ghz (tried 4.2ghz but got blue screen on torture test about 10 mins in)

I didn't want to run my QPI/VTT at the 1.515 or 1.4x levels, since that seemed pretty high to a fair
number of Overclockers. But to lower the voltage meant i couldn't run the uncore at 4ghz. As soon
as you drop from 4ghz uncore, 2000mhz mem speeds aren't feasible (since uncore must be 2x mem speed).
At least as a i understand it.

Thus, because my next memory multiplier put my memory at 1600 (at 200 blk/ 20 clock), i could drop my uncore
all the way down to 3.2 or 3.4 ghz. I suppose i could fiddle with weuntonchable's suggestion to play around
with clock, to find a new blk/clock combo, that would make more use of my memory (rated for 2133mhz).


June 29, 2009 10:20:26 PM

Ouch, failing intel burn in tests, even at stock speeds....?
June 29, 2009 11:01:53 PM

Ok passing intel burn tests....on stock now,
seems the culprit was setting memory to 1.5v

my memory is 2133 at 1.65 volts, but specs at lower speeds with 1.5v.
I had the memory running at 1600mhz at 1.5 volts.
Seems the lower voltage, causes the memory to behave erratic.

So i set Dram voltage to 1.66 (gigabyte exetreme mother boards 1.64 or 1.66,
can't hit 1.65 on the nose). But shouldn't matter because within 0.5v of vcore and QPI. So still safe i assume,
right? Ok going back to try to get some stable OC settings.
June 30, 2009 2:22:53 AM

All stable now at 4.0GHZ, 1600 Mem speed, passing intel burn test 10x!
Pretty Happy with my overclock now, so i can stop. Just can't use the next mem multiplier without using potentialy unsafe voltages on QPI/VTT, to get the uncore frequency up. Not worth the risk, so gonna stay here at 1600.








June 30, 2009 7:25:07 AM

dave_74 said:
My system:
1) i7 920 intel processor, D0 Step
2) Gigabyte extreme MB, with the optional NorthBridge heatsink installed.
3) Liquid cooling, CPU only
4) HAF case.

Current Overclocks:
1) CPU 4.0 GHZ
2) Memory: 2000 MHZ at 7-7-7-18 timings
3) QPI 7.2 GT
4) Northbridge 4000 MHZ

My question is whether my voltages are set to dangerous levels or not?
I followed the advice of the gigabyte marketing/tech guy,
and set my voltages for:

(the gigabyte guide: http://images.tweaktown.com/imagebank/Core%20i7%20920%2...(ENG).pdf)

CPU Vcore: 1.40
QPI/VTT Voltage: 1.515
Dram Voltage 1.64 (within 0.5V of Vcore/QPI)

All my other voltages are set at defaults (i think).

My temperatures under load for the CPU is 48 Celsius, under 30+ min
Prime-95 8 thread "Large FTT/torture" test.

I'm new to Overclocking, and don't know if most people try to keep their QPI/VTT
voltage lower due to temperature concerns (which probably aren't an issue for me
given my cooling system), or whether this voltage is too much even with good cooling.

Any thoughts? System seems rocksolid right now, no blue screens, errors,
and cool temps under load.



Just a question, but where did you get the D0 step?
June 30, 2009 9:13:12 AM

ebay.... from this guy http://myworld.ebay.com/pao_revolt

I gave him excellent feedback, $299 free shipping, and he was selling specifically D0 step/SLBEJ processors. Don't see his ad up any longer, but he had about 40 of them to sell.

u can also try tankguys: http://www.tankguys.com/intel-core-i7-920-d0.html

newegg, tigerdirect, and a few others couldn't be bothered to distinguish what model they ship ya, so i passed on them.
!