Radeon HD 4870 X2 vs Radeon HD 7990

Intro

Compare all of that to the Radeon HD 7990, which has core speeds of 950 MHz on the GPU, and 1500 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 TAUs and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4870 X2		350 Watts
Radeon HD 7990		375 Watts
	Difference: 25 Watts (7%)

Memory Bandwidth

The Radeon HD 7990 should in theory perform a lot faster than the Radeon HD 4870 X2 overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 4870 X2		230400 MB/sec
	Difference: 345600 (150%)

Texel Rate

The Radeon HD 7990 is much (more or less 305%) more effective at texture filtering than the Radeon HD 4870 X2. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 4870 X2		60000 Mtexels/sec
	Difference: 183200 (305%)

Pixel Rate

The Radeon HD 7990 should be much (more or less 153%) faster with regards to anti-aliasing than the Radeon HD 4870 X2, and should be capable of handling higher resolutions without slowing down too much. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 4870 X2		24000 Mpixels/sec
	Difference: 36800 (153%)

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 transported past the external memory interface within a second. It's calculated by multiplying the bus width by the speed of its memory. If the card has DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 are processed in one second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, 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 that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.