Radeon HD 6750 vs Radeon HD 7990

Intro

Compare that to the Radeon HD 7990, which makes use of a 28 nm design. AMD has set the core frequency at 950 MHz. The GDDR5 RAM runs at a speed of 1500 MHz on this particular card. It features 2048 SPUs along with 128 Texture Address Units and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 6750		86 Watts
Radeon HD 7990		375 Watts
	Difference: 289 Watts (336%)

Memory Bandwidth

Theoretically, the Radeon HD 7990 should perform much faster than the Radeon HD 6750 overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 6750		64000 MB/sec
	Difference: 512000 (800%)

Texel Rate

The Radeon HD 7990 is a lot (more or less 832%) better at texture filtering than the Radeon HD 6750. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 6750		26100 Mtexels/sec
	Difference: 217100 (832%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7990 is superior to the Radeon HD 6750, by a large margin. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 6750		11600 Mpixels/sec
	Difference: 49200 (424%)

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 max amount of data (counted in megabytes per second) that can be transferred over the external memory interface within a second. It's worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.