anyways, im a big oblivion fan and i started playing it like 2 months ago, and it worked very good, now after not playing it for a while, it detected my system specs and put it to high, but it lags so bad(unlike before, worked smooth).
i have 1 GB of ram, intel core 2 cpu 6300 @ 1.86Ghz, and Sapphire RADEON X1600 PRO.
note that oblivion worked on everything maxed at 1024x768 without AA and maybe some distance and shadows off...
what should i do ?
just set your graphics settings to how they were before when everything worked.. if that doesn't work then it's a software problem.
What actually caused the problem? You ran an Oblivion system test? If so then lower the resolution to one that offers a more acceptable frame rate. You may also want to drop AA as that's one of the major performance killers. If you made changes to your graphics card drivers/software then reset them to factory defaults. There should be an option to do that somewhere.
Also make sure you've got the latest drivers for your GPU by looking on the manufacturer's website.
There's a couple of mods that help you with bad framerates. Browse around for them. A few that come to mind are the Operation Optimization project, a simple mod called Streamline, and various lower-poly texture packs.
Also, try disabling grass (slide all the way to the left) and see if that helps. Grass is a real killer. (seriously)
I second Oldblivion. I wouldn't be able to play it on my laptop at all, but that mod makes it possible. I believe it is now updated for Shivering Isles, but last I saw the mod was in Beta. Anyone have any further info on that?
As far as desktop, I've got a Nvidia 8600gt, factory overclocked and I can max out my graphics with a little AA. I don't have the biggest screen resolution, though. I think I keep mine at 800 x 600 or the one just above that. You might want to try lowering your screen resolution too along with the above suggestions from other posters.