Radeon HD 7990 vs Radeon RX 6800

Intro

Compare those specifications to the Radeon RX 6800, which has clock speeds of 1700 MHz on the GPU, and 2000 MHz on the 16384 MB of GDDR6 memory. It features 3840 SPUs along with 240 Texture Address Units 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

The Radeon HD 7990 should in theory be just a bit faster than the Radeon RX 6800 overall. (explain)

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

Texel Rate

The Radeon RX 6800 should be quite a bit (approximately 68%) faster with regards to 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 using high levels of AA is important to you, then the Radeon RX 6800 is a better choice, by a large margin. (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: Memory bandwidth is the maximum amount of data (measured in megabytes per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the bus width by its memory clock speed. If the card has DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 maximum number of pixels the video card could possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.