GeForce GT 640 DDR3 vs Radeon HD 5570

Intro

Compare those specs to the Radeon HD 5570, which uses a 40 nm design. AMD has clocked the core speed at 650 MHz. The DDR3 memory works at a speed of 900 MHz on this particular card. It features 400(80x5) SPUs as well as 20 Texture Address Units and 8 Rasterization Operator 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 should theoretically 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 quite a bit (about 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

If running with a high screen resolution is important to you, then the GeForce GT 640 DDR3 is superior to the Radeon HD 5570, by a large margin. (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 largest amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. The number is calculated by multiplying the bus width by its memory clock speed. In the case of DDR memory, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 are applied in one second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the graphics 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 most pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka 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, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.