The following values are based on different reviews and can actually differ due to low processor power or lower clocked graphics cards. It should only give a general impression, which games should be playable. If not stated otherwise, the benchmarks were recorded without Antialiasing (AA) and Anisotrope Filtering (AF).

Gears of War: 1280x800, default (medium-high): 35 fps -> well playable with seldom stuttering
Call of Juarez : 1280x800, DX10: 20 fps -> barely playable
Company of Heroes: 1440x900, high details-> playable (not completely fluent)
World in Conflict: 1024x768, medium details (DX9), Benchmark: 23 fps -> playable (DX 10 not playable)
F.E.A.R.: 1024x768, CPU max, GPU max: 24-40 fps -> well playable
Command and Conquer 3 (C&C 3): 1024x768, high details: 30 fps well playable
Supreme Commander: 1024x768, high details: 16-44 fps -> playable (large Multiplayer battles may need a faster GPU)
Colin McRae Dirt: 1024x768, high: 20 fps -> barely playable (reduce details)
S.T.A.L.K.E.R.: 1024x768, maximum quality: 18 fps not playable -> with reduced details playable
Splinter Cell - Chaos Theory: 1280x800 -> well playable
Oblivion: 1280x800, max details: 40 fps -> well playable
Half Life 2 - Episode 1: 1280x800: 70 fps -> well playable
Prey: 1280x800: 40 fps -> well playable
Anno 1701: 1024x768, high Details: 48 fps -> well playable
Doom 3: 1024x768, Details: Ultra: 67 fps -> well playable
Age of Empires 3: 1024x768, hohe Details (without footprints), Skirmish zu 8t: 30-40 fps -> well playable
Quake 3 Arena: 1024x768, max Details: 236.5 fps -> well playable
Crysis - GPU Benchmark :  1024x768, low Details: 46 fps -> well playable