Radeon HD 3870 1GB vs Radeon HD 7990

Intro

Compare those specs to the Radeon HD 7990, which makes use of a 28 nm design. AMD has set the core frequency at 950 MHz. The GDDR5 memory is set to run at a frequency of 1500 MHz on this particular card. It features 2048 SPUs along with 128 TAUs and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 1GB		106 Watts
Radeon HD 7990		375 Watts
	Difference: 269 Watts (254%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7990 should in theory be much superior to the Radeon HD 3870 1GB overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 3870 1GB		72000 MB/sec
	Difference: 504000 (700%)

Texel Rate

The Radeon HD 7990 will be a lot (about 1861%) better at anisotropic filtering than the Radeon HD 3870 1GB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 3870 1GB		12400 Mtexels/sec
	Difference: 230800 (1861%)

Pixel Rate

The Radeon HD 7990 will be a lot (more or less 390%) better at full screen anti-aliasing than the Radeon HD 3870 1GB, and able to handle higher screen resolutions more effectively. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 3870 1GB		12400 Mpixels/sec
	Difference: 48400 (390%)

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 data (counted in MB per second) that can be moved past the external memory interface within a second. The number is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

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

Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.