Radeon HD 7990 vs Radeon RX 6800 XT

Intro

Compare all of that to the Radeon RX 6800 XT, which has GPU clock speed of 1825 MHz, and 16384 MB of GDDR6 RAM set to run at 2000 MHz through a 256-bit bus. It also is made up of 4608 Stream Processors, 288 Texture Address Units, and 128 ROPs.

Display Graphs

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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

Theoretically speaking, the Radeon HD 7990 should perform 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 should be quite a bit (about 116%) more effective at texture filtering than the Radeon HD 7990. (explain)

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

Pixel Rate

The Radeon RX 6800 XT will be quite a bit (approximately 284%) better at full screen anti-aliasing than the Radeon HD 7990, and also will be able to handle higher screen resolutions without losing too much performance. (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 max amount of information (counted in megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. 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 texture map elements (texels) that are applied per second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.