Overclocking and Stability Testing

Since we're using a 200FSB (800MHz) ABIT IS7-G motherboard, the first thing I wanted to try was what are the tightest timings I could run the TWINX at at 200FSB. After a bit of tweaking, it seems that 2-3-3-5 is about as low as I can go.

200FSB (400MHz) @ SPD	200FSB (400MHz) @ Tweaked

With that out of the way, I did a double check if the ram can indeed handle the 250FSB at 3-4-4-8. One thing I noticed that at the SPD settings, the timings were 3-4-4-7 (as was the case at 200FSB). This was confirmed using CPU-Z, so I guess the ram is slightly tweaked out of the factory.

Next thing we did was to adjust the timings and to see what the TWINX would allow us to tweak to. At 250FSB, the best we managed was…

250FSB (500MHz) @ Tweaked

The ram was completely stable, and passed MemTest without any problems at 2.5-4-3-6. Memory voltage did need a boost to 2.7 though. How about OCing a little further? At these timings...

251FSB (502MHz) @ Tweaked

We only managed to get as high as 251FSB. I managed to get into Windows at 253FSB, but the PC would immediately reboot after. Memory voltage was at the ABIT IS7's maximum, 2.8v, and the CPU was cooking along at 1.8v. We moved the timings back to 3-4-4-8, and gave it another go, but the system would never pass 255FSB. After a few phone calls, and more testing, it has been confirmed by both ABIT and Corsair that the IC7 and IS7 series have a memory FSB issue at 255 and up. ABIT is working on it though, and a fix should be available in the near future.

Obviously, we weren't going to call it a day, so we swapped the ABIT IS7 out, and dropped an Asus P4C800-E in its place. Like the ABIT board, we were able to match the above 200FSB and 250FSB timings, but we weren't able to improve upon them. Our maximum overclock was a different story.

272FSB Max OC

To be able to run your ram 1:1 at 272FSB is simply amazing. When we pushed to 273, MemTest failed, but the system still ran. The TWINX didn't seem to like any timing adjustments at this speed though, as we could never stay stable once we got into Windows.

Just to clear something up, our 2.4C can do in excess of 300FSB using a 5:4 ratio, but that isn't the point here. We are trying to test for the maximum memory OC, and our board does not offer options where the memory can run faster than the CPU FSB.

Test Setup

Asus P4C800-E: Pentium 4 2.4C, 2 x 512MB Corsair TWINX1024-4000, ATI AiW Radeon 9700 Pro, 80GB Western Digital, Windows XP SP1, ATI Catalyst 3.5.

Test Software for both platforms will be:

AVI-to-MPG Encoding
Unreal Tournament 2003
Splinter Cell

Unfortunently, I do not have any 512MB/PC4000 sticks of competing products. We will be presenting benchmarks at 200FSB, 250FSB and the maximum OC on the P4C800-E, all in Dual Channel mode.