GeForce 8600 GT 512MB DDR2 vs Radeon HD 4890 2GB

Intro

Compare those specifications to the Radeon HD 4890 2GB, which uses a 55 nm design. AMD has clocked the core speed at 1000 MHz. The GDDR5 RAM runs at a frequency of 975 MHz on this model. It features 800(160x5) SPUs along with 40 TAUs and 16 Rasterization Operator Units.

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 2GB		190 Watts
	Difference: 143 Watts (304%)

Memory Bandwidth

Performance-wise, the Radeon HD 4890 2GB should theoretically be much superior to the GeForce 8600 GT 512MB DDR2 overall. (explain)

Radeon HD 4890 2GB		124800 MB/sec
GeForce 8600 GT 512MB DDR2		12800 MB/sec
	Difference: 112000 (875%)

Texel Rate

The Radeon HD 4890 2GB is quite a bit (approximately 363%) more effective at texture filtering than the GeForce 8600 GT 512MB DDR2. (explain)

Radeon HD 4890 2GB		40000 Mtexels/sec
GeForce 8600 GT 512MB DDR2		8640 Mtexels/sec
	Difference: 31360 (363%)

Pixel Rate

The Radeon HD 4890 2GB is quite a bit (about 270%) more effective at FSAA than the GeForce 8600 GT 512MB DDR2, and also will be capable of handling higher screen resolutions better. (explain)

Radeon HD 4890 2GB		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: Memory bandwidth is the maximum amount of information (in units of megabytes per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, 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 maximum number of pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the core speed of the card. 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 lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.