GeForce 8600 GT 512MB GDDR3 vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which comes with core speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs along with 128 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8600 GT 512MB GDDR3		47 Watts
Radeon HD 7990		375 Watts
	Difference: 328 Watts (698%)

Memory Bandwidth

In theory, the Radeon HD 7990 is 2471% quicker than the GeForce 8600 GT 512MB GDDR3 in general, due to its higher bandwidth. (explain)

Radeon HD 7990		576000 MB/sec
GeForce 8600 GT 512MB GDDR3		22400 MB/sec
	Difference: 553600 (2471%)

Texel Rate

The Radeon HD 7990 is much (approximately 2715%) faster with regards to texture filtering than the GeForce 8600 GT 512MB GDDR3. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce 8600 GT 512MB GDDR3		8640 Mtexels/sec
	Difference: 234560 (2715%)

Pixel Rate

The Radeon HD 7990 will be much (approximately 1307%) faster with regards to AA than the GeForce 8600 GT 512MB GDDR3, and should be capable of handling higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce 8600 GT 512MB GDDR3		4320 Mpixels/sec
	Difference: 56480 (1307%)

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 (measured in megabytes per second) that can be transported over the external memory interface in one second. The number is calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

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