GeForce 9800 GX2 vs Radeon HD 4790

Intro

Compare those specs to the Radeon HD 4790, which comes with a GPU core clock speed of 600 MHz, and 512 MB of GDDR5 memory running at 800 MHz through a 256-bit bus. It also is made up of 640(128x5) SPUs, 32 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The GeForce 9800 GX2 should theoretically be much faster than the Radeon HD 4790 in general. (explain)

GeForce 9800 GX2		128000 MB/sec
Radeon HD 4790		102400 MB/sec
	Difference: 25600 (25%)

Texel Rate

The GeForce 9800 GX2 should be quite a bit (approximately 300%) more effective at AF than the Radeon HD 4790. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 4790		19200 Mtexels/sec
	Difference: 57600 (300%)

Pixel Rate

The GeForce 9800 GX2 should be much (more or less 100%) more effective at FSAA than the Radeon HD 4790, and also should be able to handle higher screen resolutions while still performing well. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
Radeon HD 4790		9600 Mpixels/sec
	Difference: 9600 (100%)

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 (counted in MB per second) that can be transported over the external memory interface in one second. The number is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.