Radeon HD 7990 vs Radeon RX 6800

Intro

Compare all that to the Radeon RX 6800, which has a core clock frequency of 1700 MHz and a GDDR6 memory speed of 2000 MHz. It also uses a 256-bit bus, and makes use of a 7 nm design. It features 3840 SPUs, 240 TAUs, and 96 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon RX 6800		250 Watts
Radeon HD 7990		375 Watts
	Difference: 125 Watts (50%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7990 should in theory be just a bit better than the Radeon RX 6800 in general. (explain)

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

Texel Rate

The Radeon RX 6800 should be much (about 68%) better at AF than the Radeon HD 7990. (explain)

Radeon RX 6800		408000 Mtexels/sec
Radeon HD 7990		243200 Mtexels/sec
	Difference: 164800 (68%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon RX 6800 is the winner, and very much so. (explain)

Radeon RX 6800		163200 Mpixels/sec
Radeon HD 7990		60800 Mpixels/sec
	Difference: 102400 (168%)

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 largest amount of data (measured in megabytes per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per 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 outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.