GeForce GT 640 DDR3 vs Radeon HD 7790

Intro

Compare all that to the Radeon HD 7790, which comes with GPU core speed of 1000 MHz, and 1024 MB of GDDR5 RAM set to run at 1500 MHz through a 128-bit bus. It also is made up of 896 SPUs, 56 TAUs, 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 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

Theoretically speaking, the Radeon HD 7790 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 will be a lot (approximately 94%) better 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 is a little bit (about 11%) more effective at FSAA than the GeForce GT 640 DDR3, and also able to handle higher screen resolutions while still performing well. (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: Memory bandwidth is the max amount of information (measured in MB per second) that can be transported over the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, it must be multiplied by 2 once 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 higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.