I've tried using Virtual PC and DosBox with Flight Simulator 5.1 with mixed results. On VPC, the framerate is very, very good, but sound is horrible and the drop down menus are messed up. On DosBox, everything runs fine, but the framerate is very choppy. How can I improve the framerate?

Here are my specs:

1. Motherboard = GIGABYTE GA-M61P-S3 AM2 NVIDIA GeForce 6100 ATX AMD
2. Processor type and speed = AMD64x2 Dual 5200+, 2.61ghz
3. Amount and type of RAM = 2 gig Kingston 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
4. Video board w/ RAM amount and type = onboard, Nvidia 6100
5. Sound board = Onboard, Realtek ALC883
6. Operating system = XP Pro sp2
7. Game name = Flight Simulator 5.1 CD
8. Description of problem = Slow framerate
9. Reproducibility of problem = Always
10. Sound mode used = SoundBlaster Pro/16/AWE32 (in game)
11. Video mode = Vesa 1.2 compatible, all modes tried (in game)
12. Version of emulator = DosBox 0.70
13. Steps already attempted to solve the problem = Tried some other video drivers, switched from SVGA to VGA, but frame rate is still low. Works okay in 386 mode, but then the graphics are FS4 quality.