GeForce 8600 GT 512MB DDR2 vs Radeon HD 4890 1GB

Intro

Compare all of that to the Radeon HD 4890 1GB, which features a core clock speed of 1000 MHz and a GDDR5 memory speed of 975 MHz. It also features a 256-bit memory bus, and uses a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8600 GT 512MB DDR2		47 Watts
Radeon HD 4890 1GB		190 Watts
	Difference: 143 Watts (304%)

Memory Bandwidth

In theory, the Radeon HD 4890 1GB should be a lot faster than the GeForce 8600 GT 512MB DDR2 overall. (explain)

Radeon HD 4890 1GB		124800 MB/sec
GeForce 8600 GT 512MB DDR2		12800 MB/sec
	Difference: 112000 (875%)

Texel Rate

The Radeon HD 4890 1GB should be a lot (approximately 363%) better at AF than the GeForce 8600 GT 512MB DDR2. (explain)

Radeon HD 4890 1GB		40000 Mtexels/sec
GeForce 8600 GT 512MB DDR2		8640 Mtexels/sec
	Difference: 31360 (363%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 4890 1GB is a better choice, by far. (explain)

Radeon HD 4890 1GB		16000 Mpixels/sec
GeForce 8600 GT 512MB DDR2		4320 Mpixels/sec
	Difference: 11680 (270%)

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 past the external memory interface within a second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.