choppy framerate

[Servatis]

So i've been having this problem for a while now. about 4 weeks i guess. after downloading a new snapshot.
I thought that it might correct itself with a new snapshot or updated drivers but it hasn't.

my fps hovers around 50-60 but a few times every second it drops below 10. like a little hickup in the frame rate.
the funny thing is, on maps like black mesa and green valley, it doesn't happen very often.
but throw me on a 2011 SX track and and it gets to the point where it starts to really affect my riding.

Having the frame rate drop on the face of a jump or worse in the middle of a rut is really affecting my lap times. I used to be able to get top 3 about 75% of the time.
now I'm lucky if i get in the top 5.

I have the latest drivers for everything. I can play skyrim and battlefield 3 on high graphics. My CPU has always been able to cope with MXS easily.

I know this is a very vague problem and I don't have a clue what might be causing it, but at this point i can say with 99% certainty it's not my PC.

I'm at a loss and MXS, especially SX, really isn't as fun as it was for 2 years.
a game that requires as much concentration as this can't be played with bad fps.

[jlv]

Does it still stutter when you aren't moving?

[Robert196]

Does it still stutter when you aren't moving?

I have this problem sometimes, never pay attention to when, but when it does happen, yes.

[jlv]

If it happens when you're moving, it might be stuttering when it's updating the terrain textures. If it happens when you're not moving, there's probably another process using the CPU.

[Servatis]

for me it only happens when i'm moving.

already tried turning off all unnecessary processes but that doesn't change anything.

[jlv]

Try lowering the ground texture resolution. Try all the possible settings for "terrain rendering method" too.

[Servatis]

will do when i get back home in a few days.
I did find some rogue ATI drivers from my last video card that didn't get removed propperly. but I didn't have much time to test it.