Help Overclocking E6750 (650i Chipset)

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30 Oct 2002
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Hi there,
I'm having some trouble overclocking my E6750 - the best I've managed so far, which seemed relatively stable, is 3.2GHz. This is slightly disappointing as I was hoping to hit at least 3.4GHz. My hardware:

C2D E6750 (Step B, Rev G0)
Gigabyte GA-N650SLI-DS4 Motherboard (F7 Bios)
2x 1GB OCZ Reaper PC6400 RAM
Thermalright XP120 + Noiseblocker 120mm SX1 Fan

First of all I dropped the multiplier and pushed the RAM to find its limit. The best I achieved was:
424Mhz (848DDR) 4-5-5-15 2T, 2.2V (Northbridge +0.2V, FSB +0.2V)

Whilst I found this slightly disappointing, it's not all that bad.


Then I held the RAM at 800 (or less) whilst pushing up the CPU speed. At stock voltages, I managed to get to 3.1GHz (8 x 387.9) then had to push the voltages hard to get 3.2GHz (8 x 400):
NB +0.3V, FSB +0.3V, SB +0.3V, VCC12 +0.2V, CPU 1.55V (read as 1.504V)

I've also tried turning the various speedstepping things off and on, but that doesn't seem to make much difference. I also dropped the LDT to 4x to hit those speeds.


At the current CPU overclock I don't even need to push my RAM at all, so that disappointing first RAM go was not even needed! I'm sure I'm missing something fairly crucial here, so any comments or suggestions are really appreciated.


Oh also, I tried to push it to 3.3GHz (8 x 413), syncing the RAM and also having the RAM at stock. I had all the voltages on the mobo maxed out, and the CPU at 1.5875V and it still wouldn't boot.
 
u mentioned dropping the multi to test the ram limits, did u lock that to find the fsb limit as well ?

what cpu temps are you getting ?
 
Sorry I don't understand - lock what exactly?

I turned the CPU multi to 6X, then set it to unlinked and started pushing up the RAM frequency.

I'm fairly sure the CPU temps aren't a problem - even at 3.2GHz with 1.55V and no speed stepping enabled, under full load Core Temp reports 60C, Speedfan reports less. I thought you could hit 70C before any throttling kicked in? Also that was with the BIOS running the fan speeds - perhaps I should just set them to 100% and see where I get to? I know that drops the load voltages by 10-15C.
 
best bet is turn off the speed step and fan speed control, run it at 100% while you're checking it out.

sorry locked = unlinked so you can set the memory speed to its default.

under air cooling 1.55 is on the very limits of what you should be pushing through it, 1.4-1.5v is generally the average in my experience.

make sure you manually set the memory voltage to within the acceptable range for you're make/model.

"NB +0.3V, FSB +0.3V, SB +0.3V" that should be the maximum, really shouldn;t need that for a stable overclock, personally i'd keep them to 0.1, but that might just be me.

as the memory is unlinked, voltages and extra voltages have been set you should be able to up the fsb to increase the processor speed, what ever you get that too will be you're limit.

to be honest it might just be you're unlucky and reached the limit of you're chip :(.

hopefully someone that has the mobo might know a trick or 2 perculiar to it that will get something extra out of it.
 
Ah ha - it appears I met with a 'memory hole'. For some reason it didn't want to be around the 410-415 mark.

I've now it running at 3.6GHz initially stable (8 x 450) - can't quite get it to stay stable under Orthos at 3.67GHz (8 x 460) even with a pile of extra volts.

I think I will work at 3.6GHz and try to bring the voltages down as far as they will go to keep this thing cooler and quieter. Then tighten the timings as much as possible on the RAM to squeeze every last drop of performance out of it :)

Thanks for the helps :)
 
nice one :D

dont worry too much about the ram timings, unless you're benchmarking it never seems to make much difference.

the balance is getting the best overclock with the best temps, so while u like 3.6, if the voltage is 1.5 and load temp is 60, you might be better with 3.4 using 1.4v and load temp of 50 etc.
 
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