I've just installed Sonic Riders on my PC and got the game up and running. The intro and menu are run perfectly, but when I get into the races the framerate drops to about 10fps. And yet I seem to meet all the minimum requirements specified in the ReadMe file:
WINDOWS MINIMUM
Microsoft Windows 2000 or XP
Intel Pentium III or AMD equivalent running at 1.0 GHz or higher
128 MB System RAM
8x DVD ROM Drive
3 GB Free Hard Disk Space
640 X 480 - 16 bit (High Colour) display
DirectX: DirectX 9.0c Run-Time Library
Graphics Card: DirectX 8 equivalent or above
        : Direct3D compatible video card with 64 MB VRAM or higher
Sound Card: Direct Sound compatible sound card
Windows compatible keyboard and mouse
Just for the record, I can run Mega Man X8 on my PC (which is a 3D game of roughly similar performance) without any slowdown or glitches. I also ran DirectX Diagonistic Tool tests without any problems, so I don't really understand what's causing the slowdown. Here are my specs:
Pentium 4 3.0Ghz
Intel 82865G Graphics Controller (96MB)
SoundMAX Digital Audio
512MB of RAM
DirectX 9.0c
First, if you have Norton Antivirus, it makes a game chug in general. Second, Sega PC games are rather iffy.
Example: on my computer running 98, my copy of Sonic R can't play sound effects and otherwise chugs, but Daytona USA runs flawlessly. Daytona is an older game, but it's still otherwise more graphics intensive.
Oh, and welcome to the Mobius Forum. 🙂
Suicide. It solves everything 
Yeah, I heard that one in the other Sonic Riders thread, SonicV2. Thanks for nothing. 
You're welcome. 😛
And welcome to the forums 
Have you tired lowering the graphics settings? They may be set fairly high.
Hell, I can't even change the controller settings! The configuration options are extremely limited.
