GeForce 8800 GTS (G80) 640MB vs Radeon HD 4870 512MB

Intro

Compare all of that to the Radeon HD 4870 512MB, which makes use of a 55 nm design. AMD has clocked the core speed at 750 MHz. The GDDR5 memory is set to run at a frequency of 900 MHz on this particular model. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 GTS (G80) 640MB		143 Watts
Radeon HD 4870 512MB		150 Watts
	Difference: 7 Watts (5%)

Memory Bandwidth

Theoretically, the Radeon HD 4870 512MB should be a lot faster than the GeForce 8800 GTS (G80) 640MB overall. (explain)

Radeon HD 4870 512MB		115200 MB/sec
GeForce 8800 GTS (G80) 640MB		63360 MB/sec
	Difference: 51840 (82%)

Texel Rate

The Radeon HD 4870 512MB is quite a bit (more or less 22%) more effective at anisotropic filtering than the GeForce 8800 GTS (G80) 640MB. (explain)

Radeon HD 4870 512MB		30000 Mtexels/sec
GeForce 8800 GTS (G80) 640MB		24624 Mtexels/sec
	Difference: 5376 (22%)

Pixel Rate

The Radeon HD 4870 512MB will be a small bit (approximately 17%) faster with regards to AA than the GeForce 8800 GTS (G80) 640MB, and should be capable of handling higher screen resolutions while still performing well. (explain)

Radeon HD 4870 512MB		12000 Mpixels/sec
GeForce 8800 GTS (G80) 640MB		10260 Mpixels/sec
	Difference: 1740 (17%)

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 (counted in megabytes per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory speed. If the card has 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 AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.