GeForce GT 640 DDR3 vs Radeon HD 7770

Intro

Compare those specifications to the Radeon HD 7770, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 memory works at a speed of 1125 MHz on this particular card. It features 640 SPUs along with 40 Texture Address Units and 16 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 7770		3180 points
GeForce GT 640 DDR3		1560 points
	Difference: 1620 (104%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7770		80 Watts
	Difference: 15 Watts (23%)

Memory Bandwidth

The Radeon HD 7770, in theory, should be a lot faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7770		72000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 14976 (26%)

Texel Rate

The Radeon HD 7770 will be quite a bit (more or less 39%) better at AF than the GeForce GT 640 DDR3. (explain)

Radeon HD 7770		40000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 11200 (39%)

Pixel Rate

If using a high screen resolution is important to you, then the Radeon HD 7770 is the winner, not by a very large margin though. (explain)

Radeon HD 7770		16000 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 1600 (11%)

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 moved past the external memory interface in one second. The number is calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the card's 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 applied per second. This figure is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.

Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.