GeForce GTX 275 vs Radeon HD 4890 1GB

Intro

Compare that to the Radeon HD 4890 1GB, which has GPU core speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 975 MHz through a 256-bit bus. It also features 800(160x5) Stream Processors, 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 GTX 275		219 Watts
	Difference: 29 Watts (15%)

Memory Bandwidth

In theory, the GeForce GTX 275 will be 2% faster than the Radeon HD 4890 1GB overall, due to its higher data rate. (explain)

GeForce GTX 275		127008 MB/sec
Radeon HD 4890 1GB		124800 MB/sec
	Difference: 2208 (2%)

Texel Rate

The GeForce GTX 275 should be quite a bit (about 27%) better at AF than the Radeon HD 4890 1GB. (explain)

GeForce GTX 275		50640 Mtexels/sec
Radeon HD 4890 1GB		40000 Mtexels/sec
	Difference: 10640 (27%)

Pixel Rate

The GeForce GTX 275 should be a little bit (more or less 11%) better at anti-aliasing than the Radeon HD 4890 1GB, and also able to handle higher resolutions without slowing down too much. (explain)

GeForce GTX 275		17724 Mpixels/sec
Radeon HD 4890 1GB		16000 Mpixels/sec
	Difference: 1724 (11%)

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.

Price Comparison

Specifications

Memory Bandwidth: Bandwidth is the max amount of data (measured in megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.