GeForce GTX 275 vs Radeon HD 4890 1GB

Intro

Compare those specs to the Radeon HD 4890 1GB, which features a core clock frequency of 1000 MHz and a GDDR5 memory frequency of 975 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It features 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.

Display Graphs

Hide Graphs

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

As far as performance goes, the GeForce GTX 275 should theoretically be a small bit superior to the Radeon HD 4890 1GB in general. (explain)

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

Texel Rate

The GeForce GTX 275 will be a lot (more or less 27%) more effective at anisotropic filtering 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 will be a small bit (approximately 11%) better at AA than the Radeon HD 4890 1GB, and capable of handling higher resolutions without losing too much performance. (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 largest amount of information (measured in megabytes per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the bus width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, 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 amount of texture map elements (texels) that are applied in one second. This is calculated by multiplying the total texture units of the card by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka 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 potential to reach the maximum fill rate.