Very strange fps problem

[Tankist]

Hello,

maybe someone can help me with a problem.

System:

Pentium III 800, WIN98 SE, Geforce 2 GTS, 128 MB RAM, Nvidia Driver 53.04, SB Live 1024, DirectX 9.0b

When playing CMBB or CMBO, every 20-30 seconds, the framerate drops dramatically (for example from 43 fps to 10 fps).

It then stays low for around 1 or 2 seconds before going back to normal.

There is no hard disk activity when this happens.

It happens in the planning phase and in the execution phase. It is independent from game activity; i.e. even when I do nothing (no scrolling, no mouse movement, etc), just watching the screen, fps drops periodically.

It is independent of driver settings for FSAA etc.

I have the programs for years and this NEVER happened before.

I uninstalled and reinstalled all drivers, cleaned the registry with a reg clean tool, checked for viruses, spyware, trojans, etc., but all to no avail.

There are no background programs running (like firewalls or anti-virus software).

The only thing I changed recently with my system was an upgrade from DirextX 8.0a to 9.0b SDK.

I noticed that in DxDiag, there are more new tabs/options etc. than in 8.0a, but I found no way to get rid of 9.0b to check, if this is the reason for the erratic behaviour.

So, some task/driver/whatever is periodically doing some cpu intensive activity when playing CM; any idea what the reason is or how I can track it down?

tia

Tankist

[Sergei]

Does this still occur if you turn ambient sound off?

[Tankist]

Yes, it happens with sound on or totally off.

Tankist

[Schrullenhaft]

If you minimize CM and do a Ctrl-Alt-Del, what programs are running ? This listing will give you a number of programs, but it won't list everything that is actually in memory that could be causing the problem.

I'm not aware of DirectX 9.0b being responsible for sudden drops in the FPS. Which utility are you using to measure FPS, FRAPS ?

Is there a particular reason that you're using v. 53.04 of the Nvidia drivers ? How long have you been using them and what was your previous version ? Did the problem not occur earlier with these same video drivers installed ?

What motherboard do you have and have you installed the chipset drivers for it ? Do you have any USB devices plugged in at the time of the 'slow down' ?

[Tankist]

I tracked it!

Because I had no more ideas about the cause for this behavior, I started ASUS Probe, a hardware monitoring tool.

I then started CMBB and after around 20 seconds, my cpu temperature rises to critical levels.

Some cpu overheating protection from the mainboard then kicks in and cuts down processor power (this is when the fps drop). The temperature falls and fps revert to normal. Then the cycle starts again.

The weird thing is, that my cpu fan (and all other fans) is running nominal (around 4000-4500 rpm), like all the years before.

Very strange.

Tankist

[Schrullenhaft]

This could be due to aging sensors. Once the temp reaches a certain point, it's possible that it just 'floods', giving higher than actual temperature readings. Since most of these sensors are soldered into the motherboard the only option most people can exercise is to turn off the over-temp warning. This is assuming that the temperature measurement isn't made by a die-based thermistor (built-into the CPU). If that's the case, then more than likely your CPU is overheating and you may need to clean out the heatsink and/or check the thermal contact between the CPU and heatsink.