Radeon HD 6750 vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which has a core clock frequency of 950 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 384-bit bus, and uses a 28 nm design. It is comprised of 2048 SPUs, 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

Performance-wise, the Radeon HD 7990 should theoretically be quite a bit superior to 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 quite a bit (approximately 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 a high resolution is important to you, then the Radeon HD 7990 is the winner, and very much so. (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: Bandwidth is the maximum amount of data (in units of MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better 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 amount of texture map elements (texels) that can be applied per second. This number is worked out by multiplying the total number of 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 applied in a second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka 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, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.