GeForce GT 640 DDR3 vs Radeon HD 6850

Intro

Compare all that to the Radeon HD 6850, which comes with a GPU core clock speed of 775 MHz, and 1024 MB of GDDR5 memory set to run at 1000 MHz through a 256-bit bus. It also is made up of 960 SPUs, 48 TAUs, 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 6850		2395 points
GeForce GT 640 DDR3		1560 points
	Difference: 835 (54%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 6850		127 Watts
	Difference: 62 Watts (95%)

Memory Bandwidth

In theory, the Radeon HD 6850 will be 124% faster than the GeForce GT 640 DDR3 overall, due to its greater data rate. (explain)

Radeon HD 6850		128000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 70976 (124%)

Texel Rate

The Radeon HD 6850 should be quite a bit (more or less 29%) better at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 6850		37200 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 8400 (29%)

Pixel Rate

If running with a high resolution is important to you, then the Radeon HD 6850 is the winner, by a large margin. (explain)

Radeon HD 6850		24800 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 10400 (72%)

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 (in units of MB per second) that can be moved over the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at handling 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 that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.