GeForce GT 640 DDR3 vs Radeon HD 7990

Intro

Compare those specifications to the Radeon HD 7990, which uses a 28 nm design. AMD has set the core speed at 950 MHz. The GDDR5 memory is set to run at a frequency of 1500 MHz on this specific model. It features 2048 SPUs along with 128 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 7990		15520 points
GeForce GT 640 DDR3		1560 points
	Difference: 13960 (895%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 7990		375 Watts
	Difference: 310 Watts (477%)

Memory Bandwidth

Theoretically, the Radeon HD 7990 should perform quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)

Radeon HD 7990		576000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 518976 (910%)

Texel Rate

The Radeon HD 7990 is quite a bit (approximately 744%) better at texture filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 7990		243200 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 214400 (744%)

Pixel Rate

If using high levels of AA is important to you, then the Radeon HD 7990 is the winner, by far. (explain)

Radeon HD 7990		60800 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 46400 (322%)

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.

One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (measured in megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 once again. If 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, HDR and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This number 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 video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output 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.