26 Apr 2009
overclocking is fun
As part of Dutchie (the X2-5050e crunching machine) being built, I bought some DDR2-1066 RAM to put into HAL (the E6400), and then put the DDR2-800 in HAL into Dutchie. As a result, I was able to overclock HAL. A LOT.
Before, my overclock was from 2.13Ghz to 2.4Ghz - a modest 12.7% overclock. The FSB would not rise about 300Mhz, no matter what I did. It kept restarting, and I wasn't sure why. I assumed it was the limit of the E6400 chip.
However, when putting in this new RAM, I had another go at overclocking. First 2.5Ghz, then 2.6Ghz, then 2.7Ghz straight off the bat! No rise in voltage required. Then 2.8Ghz, 2.9Ghz, 3.0Ghz too. I thought this was too good to be true! At 3.1Ghz, I had to detune the RAM from 4:5 to 1:1, and at 3.2Ghz I upped the voltage of the CPU a little.
Now I'm running at 405FSB, *8 multiplier = 3.24Ghz, with a small voltage change, making a 52.1% overclock! RAM is on a 1:1 divider at 5-5-6-15 timings - the RAM is rated 2.1V 5-6-6-18 @ 1066Mhz, but the MSI motherboard wont let me set it to 18, thus it won't boot properly if I stick it on a 4:5 divider (making the RAM 405(FSB)*2(DDR2)*1.25(multiplier) = 1012.5Mhz). But 1:1 Divider, making it 810Mhz, is OK at the minute.
It means I've learnt a lesson - RAM does matter quite a lot when it comes to overclocking. Also, it helps to have a decent motherboard. HAL's isn't the best.
I was also able to keep track of wPrime 32m and 1024m times as I overclocked the E6400:
A fairly linear progression over my overclock.
It also means I'm going to reclock all my PCI-E graphics cards. There was a couple of I hadn't posted yet - I'll probably post them all at once in uber Excel graphs.