Radeon HD 3870 512MB vs Radeon HD 7990

Intro

Compare those specifications to the Radeon HD 7990, which has GPU clock speed of 950 MHz, and 3072 MB of GDDR5 RAM set to run at 1500 MHz through a 384-bit bus. It also features 2048 Stream Processors, 128 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 3870 512MB		106 Watts
Radeon HD 7990		375 Watts
	Difference: 269 Watts (254%)

Memory Bandwidth

As far as performance goes, the Radeon HD 7990 should theoretically be quite a bit better than the Radeon HD 3870 512MB overall. (explain)

Radeon HD 7990		576000 MB/sec
Radeon HD 3870 512MB		57600 MB/sec
	Difference: 518400 (900%)

Texel Rate

The Radeon HD 7990 is much (about 1861%) more effective at anisotropic filtering than the Radeon HD 3870 512MB. (explain)

Radeon HD 7990		243200 Mtexels/sec
Radeon HD 3870 512MB		12400 Mtexels/sec
	Difference: 230800 (1861%)

Pixel Rate

The Radeon HD 7990 is much (approximately 390%) more effective at AA than the Radeon HD 3870 512MB, and also should be capable of handling higher resolutions more effectively. (explain)

Radeon HD 7990		60800 Mpixels/sec
Radeon HD 3870 512MB		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: Memory bandwidth is the maximum amount of data (measured in MB per second) that can be transferred across the external memory interface within a second. It's worked out by multiplying the card's interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR 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 amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.

Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of 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 rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.