Actually, I think your current system should be more than capable to handle Renegade X in Ultra-High Settings. Though I admit, I could be wrong here, as I haven't got any first-hand experience with new hardware.
The thing is, even my System, which is about 5 years old and worse than yours, can handle Renegade X High Graphics Settings. So maybe it's a problem with the drivers/windows setup? If that's the case, I'm sure there are some software/hardware pros around who know how to help.
For new good hardware, i always check this thread in the german computerbase forums.
http://www.computerbase.de/forum/showth ... p?t=215394
It's always up to date as far as I know. Even if you don't speak german, you will probably still understand the hardware lists
So... good luck