Don't what to muddy the waters but here is my rig and I have every game setting on as high as its goes including water and civ traffic,cockpit res =1024.
Even with the shkval on the sim runs very smooth, before and after "Alt Tab"
OPS: Windows 7 64-bit
Processor: Intel Core i7- 950 @ 3.06ghz
Installed Memory: 6GB DDR3
Hard disk space: Enough, just
NVIDIA GeForce GTX 460
DirectX latest version
I would have through Timm's machine would be comparable to my and should run BS2 fine.