Overclocking: More Voltage, Higher Clocks
Cranking Things Up a Notch
We curbed the limits of our Core 2 overclocking to best-represent the maximum frequencies value-seekers with this hardware will probably be using long-term. But the enthusiast in me just couldn’t stop with little or no voltage increase to these E0-stepping chips, knowing I may never again set up this aged platform for testing. Plus, I had already put a considerable amount of tweaking time into this very hardware a few years back, and still had notes handy detailing how high my chips would go, and the voltages required to get there.
At 1.45 V in the BIOS, 1.416 V at idle, or 1.384 V under load, this Core 2 Duo E8400 is stable at 4.5 GHz. It’s seen a fair amount of testing at these settings, but I’d drop voltages and top out in the 4.2-4.3 GHz range for daily use. At this high of a front-side bus frequency, I limited tweaking to CPU clock speed, and didn’t maximize the RAM configuration, running DDR2-1000 @ 5-5-5-15 timings. The Common Performance Level was left at default tRD 09. My success in RAM tweaking on this platform has come with 1 GB sticks of CAS 4 DDR2-800, and with this particular 4 GB kit, voltage requirements have far outweighed any gains.
I don’t like to push Core 2 Quad voltages as high, but would quickly reach the limits of this fairly modest Xigmatek HDT-S1283 air cooler anyway. The Q9550 is stable at 3.7 GHz set to 1.3625 V in the BIOS, resulting in 1.240 V under load. Again for daily use, I’d drop voltage a tad and be in the 3.6-3.65 GHz range, while keeping an eye on temperatures during those hot summer months. This front-side bus results in DDR2-1045 data rates, and with a little bump in voltages, I was able to further tweak the Common Performance Level to tRD 07, boosting memory bandwidth up to 8.36 GB/s.
To be honest, I originally had no intention on publishing this data, and only ran a few applications just for my own fun and knowledge. But the deeper I got into this, the more the information seemed worthy of sharing. Pushed to 4.5 GHz, the Core 2 Duo E8400 is able to match the single-threaded performance of Core i5-3570K at its 3.8 GHz Turbo Boost frequencies. While we know our K-series Core i5 itself has plenty of headroom for higher clock rates, we are still impressed by how well our four-year old E0 stepping Wolfdale-based scales. While the Core 2 Quad's gains are less impressive, we are eager to jump to the next page and see the impact during gaming.
Also, amoralman, did you read this? It's basically assuring you that your C2D is still awesome as a budget processor.
Also holy crap on 1.45 vcore on the C2D