GeForce 8800 Ultra vs Radeon HD 4870 2GB

Intro

Compare those specifications to the Radeon HD 4870 2GB, which has GPU core speed of 750 MHz, and 2048 MB of GDDR5 RAM running at 900 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 2GB		150 Watts
GeForce 8800 Ultra		171 Watts
	Difference: 21 Watts (14%)

Memory Bandwidth

In theory, the Radeon HD 4870 2GB will be 11% faster than the GeForce 8800 Ultra overall, due to its greater data rate. (explain)

Radeon HD 4870 2GB		115200 MB/sec
GeForce 8800 Ultra		103680 MB/sec
	Difference: 11520 (11%)

Texel Rate

The GeForce 8800 Ultra should be a lot (about 31%) better at anisotropic filtering than the Radeon HD 4870 2GB. (explain)

GeForce 8800 Ultra		39168 Mtexels/sec
Radeon HD 4870 2GB		30000 Mtexels/sec
	Difference: 9168 (31%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the GeForce 8800 Ultra is a better choice, and very much so. (explain)

GeForce 8800 Ultra		14688 Mpixels/sec
Radeon HD 4870 2GB		12000 Mpixels/sec
	Difference: 2688 (22%)

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 maximum amount of information (in units of MB per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the bus width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the faster 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 are applied per second. This is calculated by multiplying the total amount of 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 in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.