Slow game FPS on o/c above 3ghz

FrK · 23 Dec 2007 at 13:40

Hey all,

I have an issue overclocking my Q6600 on a P5K, with an MSI 8800GT.

I can get it stable no problem at 3.2ghz and even higher, but as soon as i break the 3ghz mark, all my games' FPS plummets. For instance, the Bioshock "menu" screen goes from 150fps to 30fps, and ingame it runs at about 15fps. This is the same with all games, it seems to generally run at 1/4 of usual FPS.

If i run the CPU at 3ghz exactly, it will run absolutely fine. As soon as i go into the BIOS and up the FSB by 1mhz which means the CPU hits higher than the 3ghz point, all games' FPS will be slashed. The very max FSB it will take for games to run smoothly is 337mhz. This results in a CPU speed of 3042mhz. Upping to 338mhz means sometimes on a restart it will work, sometimes the FPS will be poor. I guess the fluctuations in speed account for this. 339mhz will always result in slow FPS.

I know it isn't a problem with the actual FSB so to speak, as i can drop the multiplier to x8 and up the FSB and it will still work OK as long as it results in a CPU speed of below 3ghz.

I've disabled all CPU features that shouldn't be on, and temperatures are not a problem (50C full load @ 3.4ghz).
Anyone heard of this before or have a solution?
Thanks.

Mekrel · 23 Dec 2007 at 15:43

I'm going to take a stab at the PCI-E 16x slot for your graphics card is dropping to 1x speed. This is a bug that affects a lot of boards, use CPU-Z and the mainboard tab to check how fast the graphics interface is running.

The boards usually drop to 1x speed after a reboot.

FrK · 23 Dec 2007 at 16:15

You're absolutely right!

Thanks very much, any idea how i can fix this now?

I haven't yet updated my BIOS to the latest version (0801 i think : edit : i see 0805 now, gonna download and try that) , I guess that should be the next step to take? Do you know if it's fixed in this version?

Thanks again, I should have thought to look for that!

FrK · 23 Dec 2007 at 16:43

BIOS updated and now everything is perfect!!

Thanks very much for pointing this out or I woulda been head scratching for days. I feel silly for not updating my BIOS sooner though!

FrK · 27 Dec 2007 at 16:41

My jubilation was premature ... i had to restart yesterday and when i did, the link speed was down to x1 again. Another restart and it was still at x1.

I've now clocked back down to stock speeds to get it at x16 as i still want to be able to play stuff!
If this is a known issue, is there a known solution, quick fix, or temporary workaround?
Do I just keep restarting on the chance it will stick at x16?

Pneumonic · 27 Dec 2007 at 16:45

may not be related but is you PCIe bus set to auto? try setting it @ 101

Mekrel · 27 Dec 2007 at 18:04

FrK said:
My jubilation was premature ... i had to restart yesterday and when i did, the link speed was down to x1 again. Another restart and it was still at x1.

I've now clocked back down to stock speeds to get it at x16 as i still want to be able to play stuff!
If this is a known issue, is there a known solution, quick fix, or temporary workaround?
Do I just keep restarting on the chance it will stick at x16?

When you posted about your success, I was going to reply stating that last time I read about this problem it still wasn't fixed via a bios'.

My board does it, but only once you get to 1.7 vMCH (nb voltage) so I would maybe see if you can refine your overclock to use less volts in different areas but mainly the northbridge.

FrK · 28 Dec 2007 at 12:46

Thanks for the replies, I was busy yesterday and couldn't find time to get back on here.

I think I've changed my PCIE from Auto to 100, but I'll check that out .. , and my northbridge is only on 1.55v. The only other voltage I've changed is my DIMM to 2.0v. I haven't touched anything else.

I read for a while about the P5K + Q6600 and have never heard anyone discuss this problem, so I'm pretty surprised by it. Is it the P5K, or all P35 boards?

EDIT: I've checked, and my PCIE was on AUTO, so I've changed that to 101, and at the moment, the link speed is on x16. Whether it will disappear again after a restart or not, I'm not sure, from what you've said Mekrel I'm guessing there's a chance it could.

Mekrel · 28 Dec 2007 at 17:51

I've read it mainly about Asus boards to be fair, the P5B (965 series) suffered the same problem. Northbridge voltage was the way to solve it on those boards.