GeForce 8800 GTS (G80) 640MB vs Radeon HD 4770

Intro

Compare those specs to the Radeon HD 4770, which has a clock frequency of 750 MHz and a GDDR5 memory frequency of 800 MHz. It also features a 128-bit bus, and makes use of a 40 nm design. It is comprised of 640(128x5) SPUs, 32 Texture Address Units, and 16 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 63 Watts (79%)

Memory Bandwidth

The GeForce 8800 GTS (G80) 640MB should in theory perform much faster than the Radeon HD 4770 overall. (explain)

GeForce 8800 GTS (G80) 640MB		63360 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 12160 (24%)

Texel Rate

The GeForce 8800 GTS (G80) 640MB should be a bit (more or less 3%) more effective at anisotropic filtering than the Radeon HD 4770. (explain)

GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 624 (3%)

Pixel Rate

The Radeon HD 4770 should be a bit (more or less 17%) faster with regards to FSAA than the GeForce 8800 GTS (G80) 640MB, and capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 4770		12000 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 1740 (17%)

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: Bandwidth is the largest amount of information (in units of MB per second) that can be transported over the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.