Radeon HD 7770 vs Radeon HD 7990

Intro

Compare those specifications to the Radeon HD 7990, which comes with core clock speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs as well as 128 TAUs and 32 Rasterization Operator Units.

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 7770		3180 points
	Difference: 12340 (388%)

Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 7770		80 Watts
Radeon HD 7990		375 Watts
	Difference: 295 Watts (369%)

Memory Bandwidth

The Radeon HD 7990 should in theory be much faster than the Radeon HD 7770 overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 7770		72000 MB/sec
	Difference: 504000 (700%)

Texel Rate

The Radeon HD 7990 should be much (more or less 508%) more effective at AF than the Radeon HD 7770. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 7770		40000 Mtexels/sec
	Difference: 203200 (508%)

Pixel Rate

The Radeon HD 7990 is a lot (approximately 280%) more effective at full screen anti-aliasing than the Radeon HD 7770, and will be able to handle higher screen resolutions without slowing down too much. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 7770		16000 Mpixels/sec
	Difference: 44800 (280%)

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 data (in units of MB per second) that can be transferred past the external memory interface within a second. It's worked out by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.