GeForce 8600 GT 1GB GDDR3 vs Radeon HD 6990

Intro

Compare those specs to the Radeon HD 6990, which has a core clock speed of 830 MHz and a GDDR5 memory speed of 1250 MHz. It also features a 256-bit memory bus, and uses a 40 nm design. It is comprised of 1536 SPUs, 96 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8600 GT 1GB GDDR3		47 Watts
Radeon HD 6990		375 Watts
	Difference: 328 Watts (698%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 6990 will be 1329% quicker than the GeForce 8600 GT 1GB GDDR3 overall, due to its greater bandwidth. (explain)

Radeon HD 6990		320000 MB/sec
GeForce 8600 GT 1GB GDDR3		22400 MB/sec
	Difference: 297600 (1329%)

Texel Rate

The Radeon HD 6990 is a lot (approximately 1744%) faster with regards to AF than the GeForce 8600 GT 1GB GDDR3. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce 8600 GT 1GB GDDR3		8640 Mtexels/sec
	Difference: 150720 (1744%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 6990 is the winner, by far. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce 8600 GT 1GB GDDR3		4320 Mpixels/sec
	Difference: 48800 (1130%)

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: Memory bandwidth is the largest amount of data (in units of MB per second) that can be transported past the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed 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 handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.