Radeon HD 7990 vs Radeon RX 6800 XT

Intro

Compare those specs to the Radeon RX 6800 XT, which features clock speeds of 1825 MHz on the GPU, and 2000 MHz on the 16384 MB of GDDR6 RAM. It features 4608 SPUs as well as 288 Texture Address Units and 128 Rasterization Operator Units.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon RX 6800 XT		300 Watts
Radeon HD 7990		375 Watts
	Difference: 75 Watts (25%)

Memory Bandwidth

In theory, the Radeon HD 7990 should be a small bit faster than the Radeon RX 6800 XT in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon RX 6800 XT		524288 MB/sec
	Difference: 51712 (10%)

Texel Rate

The Radeon RX 6800 XT will be much (more or less 116%) better at AF than the Radeon HD 7990. (explain)

Radeon RX 6800 XT		525600 Mtexels/sec
Radeon HD 7990		243200 Mtexels/sec
	Difference: 282400 (116%)

Pixel Rate

If running with lots of anti-aliasing is important to you, then the Radeon RX 6800 XT is the winner, by a large margin. (explain)

Radeon RX 6800 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 largest 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 interface width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

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

Pixel Rate: Pixel rate is the most pixels that the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines 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 is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.