GeForce GTX 275 vs Radeon HD 4870 1GB

Intro

Compare those specifications to the Radeon HD 4870 1GB, which features a clock frequency of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also features a 256-bit bus, and makes use of a 55 nm design. It is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 1GB		150 Watts
GeForce GTX 275		219 Watts
	Difference: 69 Watts (46%)

Memory Bandwidth

Performance-wise, the GeForce GTX 275 should theoretically be a bit better than the Radeon HD 4870 1GB overall. (explain)

GeForce GTX 275		127008 MB/sec
Radeon HD 4870 1GB		115200 MB/sec
	Difference: 11808 (10%)

Texel Rate

The GeForce GTX 275 will be quite a bit (more or less 69%) more effective at AF than the Radeon HD 4870 1GB. (explain)

GeForce GTX 275		50640 Mtexels/sec
Radeon HD 4870 1GB		30000 Mtexels/sec
	Difference: 20640 (69%)

Pixel Rate

If running with high levels of AA is important to you, then the GeForce GTX 275 is a better choice, by far. (explain)

GeForce GTX 275		17724 Mpixels/sec
Radeon HD 4870 1GB		12000 Mpixels/sec
	Difference: 5724 (48%)

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: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transferred across the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR type memory, it should be multiplied by 2 once again. If 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 amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.