Following my recent upgrade to a Q6600, the time at last has come to start overclocking. I've running the the system on stock speeds whilst the system beds in. This is to ensure that I have a stable system form the start. I've also have a few problems with with Vista x64 to deal with so overclocking has been right down on the list of priorities.

The particular Q6600 I have bought has a "SLACR" stepping and a low TDP of just 95W. This makes it a superb choice for overclocking and some enthusiasts have reported running these at 3.2Ghz on stock voltages and air.

Being the precautious person I am, I've decided to take the road from the stock 2.4GHz to 3.2GHz is steps. My first step is a very realistic 2.7GHz which shouldn't be too much of a problem.

Into the BIOS then, I make the following changes:

Firstly, since most of the BIOS options are automatically set, the options I require are hidden, so I've changed the AI Overclocking option to Manual. By selecting this option, a range of options appear including the FSB frequency which is currently set to 266. This option dictates the speed of the system bus and the CPU. So, I'm going to change this to 300 which should take me to the required 2.7GHz.

Since I've changed the overall speed of the BUS, I need to make sure the memory is running at the correct frequency. Leaving the DRAM frequency on a 2/3 divider would force the memory to overclock to 900MHz. I want to keep the RAM as near as possible to 800MHZ as I can for now. So I've set the DRAM frequency to 720MHz (which is on a 5/6 ratio), which is the nearest I can get it too the quoted 800MHz of the DDR2-800.

For stability, I've set the both the CPU Spread Spectrum and PCI-E Spread Spectrum to Disabled. In addition the PCI-E frequency has been locked to 100MHz. This is because devices such as optical drives etc maybe sensitive to the higher bus speeds.

I'm going to attempt this first over clock without raising any voltages as raising these will ultimately raise the heat. I know that it's inevitable but I'm only going to raise in small amount and just enough to get the system stable.  However, the system failed to POST, so assuming this would be the vcore, I increased the vcore to 1.3v. 

The system booted and I was able to successfully run FutureMark 3dmark06 and CPC benchmarks:

NB - GPU overclocking disabled for CPU benchmarking

3DMark 06 benchmarks :

Overall score = 11,760  (SM2.0 = 4,892,  SM3.0 = 4,889,  CPU=3,868)

CPC benchmarks :

GIMP Image editing = 918 | Video encoding = 1,501 |  Multi-tasking = 748 | Overall = 1,056

Next was to stress test the system to ensure it's stability. To do this I set up a stress test session running Orthas Prime using the Gromac and Blend tests over the course of the day. Full details of my torture testing can be read here. The stress test held up well with no errors and CoreTemp showed acceptable temperatures as follows:

Core #0 idle/load = 31/42 | Core #1 idle/load = 31/42 | Core #2 idle/load = 31/43 | Core #3 idle/load = 31/43

I've lifted the stock speeds of the CPU from just 2.4Ghz to the 2.7Ghz with very little effort. My objective now is to see how things run, and look at 3GHz in the near future.

Here's a summary of the changed settings:

JumperFree Configuration Settings

AI Overclocking: Manual
FSB Frequency: 300MHz
PCI-E Frequency: 100MHz
DRAM Frequency: 720MHz (5:6 asynchronous)

CPU Spread Spectrum: Disabled
PCIE Spread Spectrum: Disabled

CPU Voltage: 1.3v