GeForce 8800 Ultra vs Radeon HD 4870 X2

Intro

Compare all that to the Radeon HD 4870 X2, which comes with a clock frequency of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also features a 256-bit memory bus, and makes use of a 55 nm design. It is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce 8800 Ultra		171 Watts
Radeon HD 4870 X2		350 Watts
	Difference: 179 Watts (105%)

Memory Bandwidth

Performance-wise, the Radeon HD 4870 X2 should theoretically be a lot better than the GeForce 8800 Ultra overall. (explain)

Radeon HD 4870 X2		230400 MB/sec
GeForce 8800 Ultra		103680 MB/sec
	Difference: 126720 (122%)

Texel Rate

The Radeon HD 4870 X2 is much (approximately 53%) more effective at AF than the GeForce 8800 Ultra. (explain)

Radeon HD 4870 X2		60000 Mtexels/sec
GeForce 8800 Ultra		39168 Mtexels/sec
	Difference: 20832 (53%)

Pixel Rate

The Radeon HD 4870 X2 is a lot (about 63%) faster with regards to AA than the GeForce 8800 Ultra, and capable of handling higher screen resolutions without losing too much performance. (explain)

Radeon HD 4870 X2		24000 Mpixels/sec
GeForce 8800 Ultra		14688 Mpixels/sec
	Difference: 9312 (63%)

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: Bandwidth is the largest amount of data (measured in megabytes per second) that can be moved across the external memory interface in a second. It's calculated by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 once again. If 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 figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels 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 ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.