GeForce 8800 GTS (G80) 640MB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which uses a 28 nm design. AMD has set the core frequency at 950 MHz. The GDDR5 memory runs at a speed of 1500 MHz on this particular model. It features 2048 SPUs as well as 128 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 GTS (G80) 640MB		143 Watts
Radeon HD 7990		375 Watts
	Difference: 232 Watts (162%)

Memory Bandwidth

In theory, the Radeon HD 7990 is 809% quicker than the GeForce 8800 GTS (G80) 640MB overall, due to its higher data rate. (explain)

Radeon HD 7990		576000 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 512640 (809%)

Texel Rate

The Radeon HD 7990 should be quite a bit (about 888%) more effective at AF than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 218576 (888%)

Pixel Rate

The Radeon HD 7990 should be much (more or less 493%) faster with regards to FSAA than the GeForce 8800 GTS (G80) 640MB, and capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 50540 (493%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the largest amount of data (in units of megabytes per second) that can be moved across the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour 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 output rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.