Radeon HD 7990 vs Radeon RX 6600 XT

Intro

Compare those specs to the Radeon RX 6600 XT, which uses a 7 nm design. AMD has clocked the core frequency at 1968 MHz. The GDDR6 RAM runs at a frequency of 2000 MHz on this specific model. It features 2048 SPUs along with 128 TAUs and 64 Rasterization Operator Units.

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

Theoretically, the Radeon HD 7990 should be quite a bit faster than the Radeon RX 6600 XT in general. (explain)

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

Texel Rate

The Radeon RX 6600 XT should be just a bit (approximately 4%) faster with regards to anisotropic 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

If using a high screen resolution is important to you, then the Radeon RX 6600 XT is superior to the Radeon HD 7990, by far. (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: Bandwidth is the maximum amount of data (in units of megabytes per second) that can be moved over the external memory interface in a second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This is worked out by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.