Overclocking issue in XP x64?

[gobucks]

I installed XP x64 back at the end of november, right after it came out. It went great, and I had zero issues, other than the lack of daemon tools support and ATI WDM drivers. It ran rock stable at my current overclocked 3000+, running at 2.55GHz, 1.45V vcore. All of a sudden, last week, it stopped working. Whenever i try to start winXP x64, the windows boot screen pops up, then just reboots. No message, no nothing. I dropped back my OC to 2.45GHz, and it successfully booted, and I even ran Prime95 stable overnight. But then the next day, when I booted, it would boot up, but then restarted within a few minutes, once again with no message. Due to the prime95 stability, it doesn't seem like a OCing issue.

So i figured maybe the SATA drive was getting corrupted; i've heard that with very high FSB speeds, SATA ports 1 and 2 can cause corrupted drives because their locks don't work right. Well, i had it plugged in to 3 and then 4, so that didn't seem like an issue. Clockgen also reported my PCIe clock to be fixed at 100MHz. So i tried installing XP 32-bit on the same drive, with the 2.55GHz overclock, and it has yet to crash. It boots just fine. So it's not the hard drive, and apparently the OC isn't causing the problem.

The only thing I can figure is that the AMD64 circuitry is not capable of sustaining an overclock, and that it runs Prime95 stable because it only uses the 32-bit parts of the CPU, which can clock higher. But that doesn't explain why it worked fine for weeks and then all the sudden decided to crap out. Does anyone have a similar situation? How did you fix it?

 

[Lukozer]

I get the exact same problem with my rig at stock settings. Once it's booted it's fine, but when booting up, it sometimes will just reboot without warning just as Windows finishes loading up. I'm still trying to determin if it is either a graphics card problem or my motherboard in general, although everything is pointing towards graphics card drivers. The strange thing is, if i set my RAM timings to anything other than Auto, even if i manually set looser timings than auto would, the system won't boot at all. I'm still mystified by it, but i'm continuing my search for an answer...

 

[CTho9305]

Due to the prime95 stability, it doesn't seem like a OCing issue.

So i tried installing XP 32-bit on the same drive, with the 2.55GHz overclock, and it has yet to crash. It boots just fine. So it's not the hard drive, and apparently the OC isn't causing the problem.

If it works when you stop overclocking, it is the overclock. If anything doesn't work properly when you're OCed, but does work otherwise, your OC isn't stable.

This is (part of) why when the OCers are saying every <Athlon xyz> runs stable at 200MHz over the rated clock AMD still isn't selling them at that speed. It's entirely possible that there is a data-dependent critical path in the chip which your tests don't hit, but XP64 uses a combination of instructions that cause the path to be hit.

But that doesn't explain why it worked fine for weeks and then all the sudden decided to crap out.

Maybe the extra dust in your heat sink pushed the temperature up just enough that some critical paths are too slow now. Maybe it's summer and your room is warmer.

By the way, your higher overclock (2.55) is about 4% faster than your lower OC (2.45) - can you notice a difference in any applications without the overclock? At theoretical best, if you had a task that took an hour before (say, DVD encoding), you'd be saving just under 2.5 minutes. If you had a game that was at 50 FPS, at best you'd reach 52FPS. Neither of those seem worth the headache to me.