Radeon HD 7990 vs Radeon RX 6900 XT

Intro

Compare those specifications to the Radeon RX 6900 XT, which features a core clock frequency of 1825 MHz and a GDDR6 memory speed of 2000 MHz. It also uses a 256-bit bus, and uses a 7 nm design. It is comprised of 5120 SPUs, 320 TAUs, and 128 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon RX 6900 XT		300 Watts
Radeon HD 7990		375 Watts
	Difference: 75 Watts (25%)

Memory Bandwidth

Performance-wise, the Radeon HD 7990 should in theory be just a bit superior to the Radeon RX 6900 XT in general. (explain)

Radeon HD 7990		576000 MB/sec
Radeon RX 6900 XT		524288 MB/sec
	Difference: 51712 (10%)

Texel Rate

The Radeon RX 6900 XT should be much (approximately 140%) better at anisotropic filtering than the Radeon HD 7990. (explain)

Radeon RX 6900 XT		584000 Mtexels/sec
Radeon HD 7990		243200 Mtexels/sec
	Difference: 340800 (140%)

Pixel Rate

If using a high resolution is important to you, then the Radeon RX 6900 XT is a better choice, by far. (explain)

Radeon RX 6900 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: Bandwidth is the maximum amount of information (counted in MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few 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.