I've had this problem ever since I built my last machine. I'm not sure whether it also existed with my previous video card but it definitely exists with my present one (EVGA Geforce 6200). When the PC is freshly rebooted, I'll get decent frame rates in Train Simulator, often up to the maximum 60 fps in lower detail areas. When my PC runs for several days straight, the maximum drops to either 32, 16, or even 8, even in areas with just grass and tracks. This occurs not just is MSTS, but also other 3D applications like BVE (Boso View Express-a Japanese freeware train simulator). Rebooting cures the problem, but for the last year and a half I've been unable to find anything which might be causing it. It would be nice to be able to have a fix not involving rebooting since the machine is otherwise stable, even when running for weeks. Note that it's not a hardware problem. When I go into hibernate, turn the machine off, and restart it the problem persists. Only a fresh reboot cures it. I've hesitated to even ask about this problem because it's minor as things go, and probably one for which a real cure might not exist.
Any help or tips are appreciated.
When this happens, do you run any frame rate benchmark tests? Have you tried turning off sound (sound driver incompatibility perhaps), to see if there is a substantial jump in fps? Have you tried lowering the resolution, and seeing if you ever get this happening at lower res (or are you limited to certain resoutions?).
Maybe some of the things mentioned in this thread from
2 years ago (almost an eternity in computer performance) might help (uninstalling all older drivers, updating to latest drivers for this now ancient/low performance GPU
)
http://forums.battlegroundeurope.com/showthread.php?t=73542
The GeForce 6200 TurboCache uses system memory that has much lower bandwidth than dedicated video memory on card. Simply put it is not a good card for gaming.
(not sure if that's true, but could be something to think about)
Do a Google search on terms: "Geforce 6200 low fps 3d"
Suggest if you ask on other gaming forums, you do a full system detail. If you are still on AGP, then options for upgrades are more limited/expensive as Nvidia is Pci-e only these days. Pci-e allows you to upgrade to inexpensive NV8000 series.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010380048+1069609639&name=AGP+4X/8X
Perhaps you can afford to upgrade (since you planned to run the next version of MSTS when it comes out on Vista?) now to an inexpensive ($40-90 range) of slightly higher performance, supports newer graphics standards (DirectX 10,etc) you might be required to have in that next gen MSTS...maybe even Merc has a spare sitting around he could send you?
You would have to do some research though, decide if you will ever need dual link dvi outputs, support for HDCP, etc, ---I forget which sites do a good job of comparisons as I don't have a desktop that I use, don't do 3d sims/gams---to figure out what will give you the most bang for the buck in terms of newer/stable-reliable/lower priced GPU's that are compatible w/your MB.