GeForce GT 640 DDR3 vs Radeon HD 6870

Intro

Compare those specifications to the Radeon HD 6870, which has GPU clock speed of 900 MHz, and 1024 MB of GDDR5 memory set to run at 1050 MHz through a 256-bit bus. It also features 1120 Stream Processors, 56 Texture Address Units, and 32 Raster Operation 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 6870		2870 points
GeForce GT 640 DDR3		1560 points
	Difference: 1310 (84%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 6870		151 Watts
	Difference: 86 Watts (132%)

Memory Bandwidth

The Radeon HD 6870, in theory, should perform much faster than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 6870		134400 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 77376 (136%)

Texel Rate

The Radeon HD 6870 is a lot (about 75%) better at texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 6870		50400 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 21600 (75%)

Pixel Rate

The Radeon HD 6870 will be much (about 100%) more effective at full screen anti-aliasing than the GeForce GT 640 DDR3, and should be capable of handling higher resolutions better. (explain)

Radeon HD 6870		28800 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 14400 (100%)

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 data (counted in megabytes per second) that can be transported over the external memory interface in one second. The number is worked out by multiplying the interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.