GeForce 9800 GX2 vs Radeon HD 4850 1GB

Intro

Compare that to the Radeon HD 4850 1GB, which comes with clock speeds of 625 MHz on the GPU, and 993 MHz on the 1024 MB of GDDR4 RAM. It features 800(160x5) SPUs as well as 40 TAUs and 16 Rasterization Operator Units.

(No game benchmarks for this combination yet.)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4850 1GB		110 Watts
GeForce 9800 GX2		197 Watts
	Difference: 87 Watts (79%)

Memory Bandwidth

The GeForce 9800 GX2, in theory, should perform a lot faster than the Radeon HD 4850 1GB overall. (explain)

GeForce 9800 GX2		128000 MB/sec
Radeon HD 4850 1GB		63552 MB/sec
	Difference: 64448 (101%)

Texel Rate

The GeForce 9800 GX2 will be much (approximately 207%) more effective at anisotropic filtering than the Radeon HD 4850 1GB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 4850 1GB		25000 Mtexels/sec
	Difference: 51800 (207%)

Pixel Rate

The GeForce 9800 GX2 will be much (about 92%) more effective at anti-aliasing than the Radeon HD 4850 1GB, and should be capable of handling higher resolutions without slowing down too much. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
Radeon HD 4850 1GB		10000 Mpixels/sec
	Difference: 9200 (92%)

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: Memory bandwidth is the max amount of information (in units of MB per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 maximum number of pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.