Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Radeon HD 6850 127 Watts
GeForce GTS 250 1GB 145 Watts
Difference: 18 Watts (14%)
Memory Bandwidth
As far as performance goes, the Radeon HD 6850 should in theory be much superior to the GeForce GTS 250 1GB in general. (explain)
Radeon HD 6850 128000 MB/sec
GeForce GTS 250 1GB 70400 MB/sec
Difference: 57600 (82%)
Texel Rate
The GeForce GTS 250 1GB will be quite a bit (more or less 27%) more effective at AF than the Radeon HD 6850. (explain)
GeForce GTS 250 1GB 47232 Mtexels/sec
Radeon HD 6850 37200 Mtexels/sec
Difference: 10032 (27%)
Pixel Rate
If using a high resolution is important to you, then the Radeon HD 6850 is the winner, and very much so. (explain)
Radeon HD 6850 24800 Mpixels/sec
GeForce GTS 250 1GB 11808 Mpixels/sec
Difference: 12992 (110%)
Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.