GeForce 8800 GTS (G80) 640MB vs Radeon HD 5770

Intro

Compare that to the Radeon HD 5770, which features a core clock speed of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 128-bit memory bus, and uses a 40 nm design. It is made up of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5770		108 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 35 Watts (32%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 5770 should be 21% quicker than the GeForce 8800 GTS (G80) 640MB overall, because of its greater bandwidth. (explain)

Radeon HD 5770		76800 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 13440 (21%)

Texel Rate

The Radeon HD 5770 will be quite a bit (approximately 38%) more effective at texture filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 5770		34000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 9376 (38%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 5770 is the winner, by a large margin. (explain)

Radeon HD 5770		13600 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 3340 (33%)

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.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.