GeForce 8800 GTS (G80) 640MB vs Radeon HD 7770

Intro

Compare those specs to the Radeon HD 7770, which has a clock speed of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is made up of 640 SPUs, 40 TAUs, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
GeForce 8800 GTS (G80) 640MB		143 Watts
	Difference: 63 Watts (79%)

Memory Bandwidth

Performance-wise, the Radeon HD 7770 should in theory be a small bit superior to the GeForce 8800 GTS (G80) 640MB in general. (explain)

Radeon HD 7770		72000 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 8640 (14%)

Texel Rate

The Radeon HD 7770 is much (about 62%) faster with regards to texture filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 15376 (62%)

Pixel Rate

The Radeon HD 7770 will be much (about 56%) better at AA than the GeForce 8800 GTS (G80) 640MB, and also should be able to handle higher screen resolutions better. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 5740 (56%)

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 largest amount of information (in units of MB per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.