Radeon HD 7870 XT vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core speed at 950 MHz. The GDDR5 RAM runs at a speed of 1500 MHz on this model. It features 2048 SPUs along with 128 Texture Address Units and 32 ROPs.

Display Graphs

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Benchmarks

These are real-world performance benchmarks that were submitted by Hardware Compare users. The scores seen here are the average of all benchmarks submitted for each respective test and hardware.

3DMark Fire Strike Graphics Score

Radeon HD 7990		15520 points
Radeon HD 7870 XT		6390 points
	Difference: 9130 (143%)

Ethereum Mining Hash Rate

Radeon HD 7990		32 Mh/s
Radeon HD 7870 XT		15 Mh/s
	Difference: 17 (113%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870 XT		185 Watts
Radeon HD 7990		375 Watts
	Difference: 190 Watts (103%)

Memory Bandwidth

The Radeon HD 7990 should theoretically perform much faster than the Radeon HD 7870 XT overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 7870 XT		192000 MB/sec
	Difference: 384000 (200%)

Texel Rate

The Radeon HD 7990 should be a lot (approximately 174%) better at AF than the Radeon HD 7870 XT. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 7870 XT		88800 Mtexels/sec
	Difference: 154400 (174%)

Pixel Rate

The Radeon HD 7990 will be a lot (more or less 105%) more effective at FSAA than the Radeon HD 7870 XT, and able to handle higher resolutions without losing too much performance. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 7870 XT		29600 Mpixels/sec
	Difference: 31200 (105%)

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 largest amount of information (measured in MB per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR memory, the result should be multiplied by 2 again. If 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 higher screen resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). 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 potential to reach the maximum fill rate.