GeForce GT 640 DDR3 vs Radeon HD 6990

Intro

Compare all of that to the Radeon HD 6990, which features a GPU core clock speed of 830 MHz, and 2048 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also features 1536 Stream Processors, 96 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 6990		5820 points
GeForce GT 640 DDR3		1560 points
	Difference: 4260 (273%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

GeForce GT 640 DDR3		65 Watts
Radeon HD 6990		375 Watts
	Difference: 310 Watts (477%)

Memory Bandwidth

Performance-wise, the Radeon HD 6990 should in theory be a lot better than the GeForce GT 640 DDR3 overall. (explain)

Radeon HD 6990		320000 MB/sec
GeForce GT 640 DDR3		57024 MB/sec
	Difference: 262976 (461%)

Texel Rate

The Radeon HD 6990 should be quite a bit (approximately 453%) better at anisotropic filtering than the GeForce GT 640 DDR3. (explain)

Radeon HD 6990		159360 Mtexels/sec
GeForce GT 640 DDR3		28800 Mtexels/sec
	Difference: 130560 (453%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon HD 6990 is the winner, by far. (explain)

Radeon HD 6990		53120 Mpixels/sec
GeForce GT 640 DDR3		14400 Mpixels/sec
	Difference: 38720 (269%)

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 maximum amount of information (in units of MB per second) that can be moved across the external memory interface in a second. It's 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 better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling 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 card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.