GeForce GT 640 DDR3 vs Radeon HD 6770

Intro

Compare those specs to the Radeon HD 6770, which has core clock speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 memory. It features 800 SPUs along with 40 Texture Address Units and 16 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

GeForce GT 640 DDR3		1560 points
Radeon HD 6770		1520 points
	Difference: 40 (3%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 6770		108 Watts
	Difference: 43 Watts (66%)

Memory Bandwidth

In theory, the Radeon HD 6770 will be 18% quicker than the GeForce GT 640 DDR3 in general, because of its higher data rate. (explain)

Radeon HD 6770		67200 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 10176 (18%)

Texel Rate

The Radeon HD 6770 will be much (about 25%) more effective at texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 6770		36000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 7200 (25%)

Pixel Rate

Both cards have exactly the same pixel rate, so in theory they should perform equally good at at AA, and be able to handle the same resolutions. (explain)

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 (in units of MB per second) that can be transferred across the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.