GeForce GT 640 DDR3 vs Radeon HD 7870 XT

Intro

Compare those specs to the Radeon HD 7870 XT, which comes with clock speeds of 925 MHz on the GPU, and 1500 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 TAUs and 32 Rasterization Operator Units.

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 XT		6390 points
GeForce GT 640 DDR3		1560 points
	Difference: 4830 (310%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7870 XT		185 Watts
	Difference: 120 Watts (185%)

Memory Bandwidth

The Radeon HD 7870 XT should theoretically be much faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 7870 XT		192000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 134976 (237%)

Texel Rate

The Radeon HD 7870 XT will be much (approximately 208%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7870 XT		88800 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 60000 (208%)

Pixel Rate

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

Radeon HD 7870 XT		29600 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 15200 (106%)

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 MB per second) that can be moved over the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better 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 texture map elements (texels) that can be applied in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.