Radeon HD 7990 vs Radeon RX 6600 XT

Intro

Compare those specs to the Radeon RX 6600 XT, which comes with a clock frequency of 1968 MHz and a GDDR6 memory frequency of 2000 MHz. It also makes use of a 128-bit bus, and makes use of a 7 nm design. It is made up of 2048 SPUs, 128 Texture Address Units, and 64 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon RX 6600 XT		160 Watts
Radeon HD 7990		375 Watts
	Difference: 215 Watts (134%)

Memory Bandwidth

The Radeon HD 7990 should theoretically perform much faster than the Radeon RX 6600 XT overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon RX 6600 XT		262144 MB/sec
	Difference: 313856 (120%)

Texel Rate

The Radeon RX 6600 XT is a bit (approximately 4%) faster with regards to texture filtering than the Radeon HD 7990. (explain)

Radeon RX 6600 XT		251904 Mtexels/sec
Radeon HD 7990		243200 Mtexels/sec
	Difference: 8704 (4%)

Pixel Rate

The Radeon RX 6600 XT will be a lot (about 107%) faster with regards to full screen anti-aliasing than the Radeon HD 7990, and will be able to handle higher resolutions without slowing down too much. (explain)

Radeon RX 6600 XT		125952 Mpixels/sec
Radeon HD 7990		60800 Mpixels/sec
	Difference: 65152 (107%)

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 transported over the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 once 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 number of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at 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 can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the clock 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 fill rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.