Radeon HD 7990 vs Radeon RX 6900 XT

Intro

Compare that to the Radeon RX 6900 XT, which comes with GPU core speed of 1825 MHz, and 16384 MB of GDDR6 memory running at 2000 MHz through a 256-bit bus. It also features 5120 Stream Processors, 320 Texture Address Units, and 128 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon RX 6900 XT		300 Watts
Radeon HD 7990		375 Watts
	Difference: 75 Watts (25%)

Memory Bandwidth

Theoretically speaking, the Radeon HD 7990 is 10% quicker than the Radeon RX 6900 XT overall, because of its higher data rate. (explain)

Radeon HD 7990		576000 MB/sec
Radeon RX 6900 XT		524288 MB/sec
	Difference: 51712 (10%)

Texel Rate

The Radeon RX 6900 XT will be quite a bit (about 140%) better at texture filtering than the Radeon HD 7990. (explain)

Radeon RX 6900 XT		584000 Mtexels/sec
Radeon HD 7990		243200 Mtexels/sec
	Difference: 340800 (140%)

Pixel Rate

If running with a high screen resolution is important to you, then the Radeon RX 6900 XT is a better choice, by a large margin. (explain)

Radeon RX 6900 XT		233600 Mpixels/sec
Radeon HD 7990		60800 Mpixels/sec
	Difference: 172800 (284%)

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 information (measured in megabytes per second) that can be transferred over the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster 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 number of texture map elements (texels) that are applied in one second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of 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.