GeForce GT 640 DDR3 vs Radeon HD 7790

Intro

Compare those specs to the Radeon HD 7790, which comes with clock speeds of 1000 MHz on the GPU, and 1500 MHz on the 1024 MB of GDDR5 RAM. It features 896 SPUs along with 56 TAUs 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

Radeon HD 7790		4330 points
GeForce GT 640 DDR3		1560 points
	Difference: 2770 (178%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7790		85 Watts
	Difference: 20 Watts (31%)

Memory Bandwidth

The Radeon HD 7790, in theory, should perform quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7790		96000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 38976 (68%)

Texel Rate

The Radeon HD 7790 should be a lot (about 94%) more effective at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7790		56000 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 27200 (94%)

Pixel Rate

The Radeon HD 7790 will be a bit (about 11%) better at full screen anti-aliasing than the GeForce GT 640 DDR3, and capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 7790		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: Bandwidth is the maximum amount of data (counted in MB per second) that can be moved past the external memory interface in a second. It is worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR type memory, it must be multiplied by 2 once 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, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the video 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 amount of pixels 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 number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.