Overclocking

After the majority of these tests were run, we decided to see what would happen if we pushed these processors a little bit beyond what they were designed to do. We should preface by saying that the Intel Desktop Board D975XBX, is not the ideal overclocking motherboard. It does, however, provide for excellent control of voltages and is a very stable motherboard.

For the Core 2 Extreme X6800, the first of the two processors we tested, the settings in the BIOS allow you to adjust pretty much everything. The only complaint we have is that the maximum overclock you can achieve via FSB increases was 30%. However, that didn’t turn out to be an issue in our tests, because we experienced some pretty serious stability issues when the processor reached anywhere much beyond 3.52 GHz. The system would boot at 3.66GHz, but that is about all it would do.

For the Core 2 Duo E6700, we managed the maximum overclock of 30%, or 800MHz, with relative ease. When we say relative ease, we mean we dialed in the settings and it booted up on the first try. Not only that, but the system was 100% stable as a rock at those speeds. In fact, we are currently preparing this article on the test bed to get a better idea of how stable the system is when running lots and lots of office productivity programs. Our overclocking methods, due to lack of time with the processors, consisted of simple and rather large FSB increases. Each stage of overclocking for each processor is chronicled below via CPU-Z screenshots.


Interesting to note here is that the RAM we used in our test bed had absolutely no problems firing up at 856MHz at stock voltage, significantly higher than its 800MHz rating. Even more interesting is the final screenshot of the E6700 running at 3455MHz with a system FSB of 1382MHz. While the motherboard technically supports 1333MHz FSB, we only had it set to 1066MHz, default, for the entire duration of our testing.

Overclocking Performance

To get a better idea of the scalability of the processor that we already had from the first few tests, we decided to use Quake 4 as our tool of choice. At low settings and low resolution, the game is just about entirely CPU limited, which would make for some interesting results. We also tested for FPS at each overclocking level at 1280x1024 resolution and medium details, in order to illustrate the point we made in the Quake 4 section about the game being graphics card limited at higher settings.




There you can see the maximum possible framerates we could achieve at each overclocked setting. While all of these numbers are impressive for how high they are, the more interesting characteristic here is that the differences in clock speed and the relation to frame rates is pretty clearly laid out (with the exception of the E6700 at 3455MHz – we have no idea how FPS actually dropped from previous configuration three times in a row).