GeForce 9800 GX2 vs Radeon HD 4890 2GB

Intro

Compare those specifications to the Radeon HD 4890 2GB, which makes use of a 55 nm design. AMD has set the core frequency at 1000 MHz. The GDDR5 RAM is set to run at a speed of 975 MHz on this 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)

Radeon HD 4890 2GB		190 Watts
GeForce 9800 GX2		197 Watts
	Difference: 7 Watts (4%)

Memory Bandwidth

In theory, the GeForce 9800 GX2 should be 3% quicker than the Radeon HD 4890 2GB in general, due to its greater data rate. (explain)

GeForce 9800 GX2		128000 MB/sec
Radeon HD 4890 2GB		124800 MB/sec
	Difference: 3200 (3%)

Texel Rate

The GeForce 9800 GX2 is much (about 92%) better at anisotropic filtering than the Radeon HD 4890 2GB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 4890 2GB		40000 Mtexels/sec
	Difference: 36800 (92%)

Pixel Rate

The GeForce 9800 GX2 should be a little bit (about 20%) more effective at FSAA than the Radeon HD 4890 2GB, and should be able to handle higher screen resolutions without losing too much performance. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
Radeon HD 4890 2GB		16000 Mpixels/sec
	Difference: 3200 (20%)

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 largest amount of information (counted in megabytes per second) that can be transported past the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is worked out by multiplying the total 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 in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number 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 drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.