Phase one - The CPU overclock
Phase one - The CPU overclock
So we'll be trying to shatter that 3Dmark Vantage record of ours in three phases. It's a plan to gain maximum stability, ensuring that we can actually have a 3DMark Vantage run finish without crashing.
We just assembled the PC, have it in working order. At this stage just one PSU and one GPU have been installed. The first stability run is completely at default settings, our memory is set at JEDEC 1066 MHz CAS9, our processor runs at its default 3.3 GHz clock frequency and the GPU is clocked at reference freqiencies as well.
We finish the 1st run. With this setup we reach a P score of roughly 19.500 points with a GPU score of roughly 17.000 points.
Everything remains cool and stable. Therefore in the first stage we'll now be overclocking the processor. In the BIOS (or if you prefer with eVGA eLEET in Windows you need to find a sweet spot for overclocking.
You gradually need to increase your CPU voltage and clock frequency, then boot into Windows and pull off a CPU stress test. The problem here is that after 4 GHz on the processor, the voltage demands of the CPU rise quickly .. and so will your temperatures.
Typically we would have preferred to have used a phase change unit to overclock the processor, but our trusty old Asetek VapoChill unit is not Socket LGA 1366 compatible. We therefore reverted back to liquid cooling. We tried several combo's of base-clock and multiplier settings and found a sweet spot of 4629 MHz on all six-cores of the Core i7 980X processor. To do so we used a base-clock of 145 MHz versus a multiplier of 32. Quite impressible with just liquid cooling really.
You can gain more performance with a higher BLC, but since this was a sweet spot for our OCZ blade memory as well with a 2:14 divider we then reached ~ 4630 MHz on the processor and where able to run 2025 MHz on the triple channel memory at CAS latency 8:9:8:24. For this setup to remain stable we inject 1.6 Volts into the processor and the memory is locked tight at 1.66 Volts.
This overclock was stable enough for 3DMark Vantage runs, but definitely not stable on the long term, we are pushing it as temperatures now reach 90 Degrees C / 195 Degrees F on the processor under short term stress. Whatever we are going to do, we'll need to do it in short and quick bursts.
But hey .. all it is required to do is finish a 3DMark Vantage session.
Phase one is complete. We have a stable enough yet massive overclock on the processor. It is time to go to phase 2.
Click images to enlarge.
