GeForce GT 640 DDR3 vs Radeon HD 7870 XT

Intro

Compare all that to the Radeon HD 7870 XT, which uses a 28 nm design. AMD has clocked the core speed at 925 MHz. The GDDR5 RAM is set to run at a speed of 1500 MHz on this model. It features 1536 SPUs as well as 96 Texture Address Units 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 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 in theory be quite a bit faster than the GeForce GT 640 DDR3 in general. (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 quite a bit (about 208%) more effective at 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

The Radeon HD 7870 XT is quite a bit (approximately 106%) better at anti-aliasing than the GeForce GT 640 DDR3, and also capable of handling higher resolutions without losing too much performance. (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: Bandwidth is the maximum amount of information (measured in MB per second) that can be moved over the external memory interface in one second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

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