Radeon HD 7870 vs Radeon HD 7990

Intro

Compare that to the Radeon HD 7990, which uses a 28 nm design. AMD has clocked the core speed at 950 MHz. The GDDR5 RAM is set to run at a speed of 1500 MHz on this model. It features 2048 SPUs as well as 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		6230 points
	Difference: 9290 (149%)

Zcash Mining Hash Rate

Radeon HD 7990		513 Sol/s
Radeon HD 7870		172 Sol/s
	Difference: 341 (198%)

Ethereum Mining Hash Rate

Radeon HD 7990		32 Mh/s
Radeon HD 7870		16 Mh/s
	Difference: 16 (100%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7870		175 Watts
Radeon HD 7990		375 Watts
	Difference: 200 Watts (114%)

Memory Bandwidth

The Radeon HD 7990 should theoretically perform quite a bit faster than the Radeon HD 7870 overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 7870		153600 MB/sec
	Difference: 422400 (275%)

Texel Rate

The Radeon HD 7990 is a lot (about 204%) more effective at AF than the Radeon HD 7870. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 7870		80000 Mtexels/sec
	Difference: 163200 (204%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7990 is superior to the Radeon HD 7870, by far. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 7870		32000 Mpixels/sec
	Difference: 28800 (90%)

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 largest amount of information (measured in MB per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 can be applied in one second. This number is worked out by multiplying the total number 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 applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.