GeForce 9800 GX2 vs Radeon HD 4890 1GB

Intro

Compare those specs to the Radeon HD 4890 1GB, which uses a 55 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM is set to run at a frequency of 975 MHz on this specific card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4890 1GB		190 Watts
GeForce 9800 GX2		197 Watts
	Difference: 7 Watts (4%)

Memory Bandwidth

Performance-wise, the GeForce 9800 GX2 should in theory be a little bit better than the Radeon HD 4890 1GB in general. (explain)

GeForce 9800 GX2		128000 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 3200 (3%)

Texel Rate

The GeForce 9800 GX2 is much (approximately 92%) more effective at texture filtering than the Radeon HD 4890 1GB. (explain)

GeForce 9800 GX2		76800 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 36800 (92%)

Pixel Rate

The GeForce 9800 GX2 is a bit (about 20%) more effective at anti-aliasing than the Radeon HD 4890 1GB, and also will be capable of handling higher screen resolutions better. (explain)

GeForce 9800 GX2		19200 Mpixels/sec
Radeon HD 4890 1GB		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 maximum amount of data (counted in MB per second) that can be transported over the external memory interface in one second. It's worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 are processed in one second. This is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.