GeForce GT 640 DDR3 vs Radeon HD 5570

Intro

Compare all of that to the Radeon HD 5570, which features a core clock speed of 650 MHz and a DDR3 memory speed of 900 MHz. It also uses a 128-bit memory bus, and uses a 40 nm design. It is comprised of 400(80x5) SPUs, 20 Texture Address Units, and 8 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 5570		43 Watts
GeForce GT 640 DDR3		65 Watts
	Difference: 22 Watts (51%)

Memory Bandwidth

The GeForce GT 640 DDR3, in theory, should be quite a bit faster than the Radeon HD 5570 overall. (explain)

GeForce GT 640 DDR3		57024 MB/sec
Radeon HD 5570		28800 MB/sec
	Difference: 28224 (98%)

Texel Rate

The GeForce GT 640 DDR3 should be much (more or less 122%) faster with regards to AF than the Radeon HD 5570. (explain)

GeForce GT 640 DDR3		28800 Mtexels/sec
Radeon HD 5570		13000 Mtexels/sec
	Difference: 15800 (122%)

Pixel Rate

The GeForce GT 640 DDR3 will be quite a bit (approximately 177%) faster with regards to AA than the Radeon HD 5570, and should be capable of handling higher screen resolutions more effectively. (explain)

GeForce GT 640 DDR3		14400 Mpixels/sec
Radeon HD 5570		5200 Mpixels/sec
	Difference: 9200 (177%)

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 (counted in MB per second) that can be moved across the external memory interface in a second. The number is calculated by multiplying the bus width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total number of texture units by the core clock 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 in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.