GeForce GTX 275 vs Radeon HD 4870 512MB

Intro

Compare that to the Radeon HD 4870 512MB, which features core clock speeds of 750 MHz on the GPU, and 900 MHz on the 512 MB of GDDR5 RAM. It features 800(160x5) SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 512MB		150 Watts
GeForce GTX 275		219 Watts
	Difference: 69 Watts (46%)

Memory Bandwidth

The GeForce GTX 275, in theory, should be a small bit faster than the Radeon HD 4870 512MB overall. (explain)

GeForce GTX 275		127008 MB/sec
Radeon HD 4870 512MB		115200 MB/sec
	Difference: 11808 (10%)

Texel Rate

The GeForce GTX 275 is a lot (approximately 69%) faster with regards to texture filtering than the Radeon HD 4870 512MB. (explain)

GeForce GTX 275		50640 Mtexels/sec
Radeon HD 4870 512MB		30000 Mtexels/sec
	Difference: 20640 (69%)

Pixel Rate

If using a high resolution is important to you, then the GeForce GTX 275 is the winner, by a large margin. (explain)

GeForce GTX 275		17724 Mpixels/sec
Radeon HD 4870 512MB		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 information (measured in megabytes per second) that can be transported across the external memory interface within a second. It's worked out by multiplying the bus width by the speed of its memory. If the card has DDR RAM, it 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 AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate 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 filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.