GeForce GT 640 DDR3 vs Radeon HD 7850

Intro

Compare those specifications to the Radeon HD 7850, which comes with a core clock frequency of 860 MHz and a GDDR5 memory frequency of 1200 MHz. It also uses a 256-bit memory bus, and uses a 28 nm design. It is comprised of 1024 SPUs, 64 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 7850		5200 points
GeForce GT 640 DDR3		1560 points
	Difference: 3640 (233%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7850		130 Watts
	Difference: 65 Watts (100%)

Memory Bandwidth

The Radeon HD 7850 should theoretically perform quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7850		153600 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 96576 (169%)

Texel Rate

The Radeon HD 7850 should be quite a bit (more or less 91%) faster with regards to anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7850		55040 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 26240 (91%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 7850 is a better choice, by a large margin. (explain)

Radeon HD 7850		27520 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 13120 (91%)

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 max amount of information (counted in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the 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 most pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.