GeForce GT 640 DDR3 vs Radeon HD 7870

Intro

Compare those specs to the Radeon HD 7870, which features a core clock frequency of 1000 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit bus, and uses a 28 nm design. It features 1280 SPUs, 80 TAUs, and 32 ROPs.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 7870		6230 points
GeForce GT 640 DDR3		1560 points
	Difference: 4670 (299%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7870		175 Watts
	Difference: 110 Watts (169%)

Memory Bandwidth

The Radeon HD 7870, in theory, should be quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7870		153600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 96576 (169%)

Texel Rate

The Radeon HD 7870 will be quite a bit (more or less 178%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7870		80000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 51200 (178%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 7870 is the winner, by far. (explain)

Radeon HD 7870		32000 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 17600 (122%)

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 maximum amount of information (measured in MB per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the bandwidth is, 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 per second. This number is worked out by multiplying the total texture units by the core 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 processed in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels 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 number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.