Radeon HD 3870 512MB vs Radeon HD 7990

Intro

Compare all that to the Radeon HD 7990, which comes with GPU core speed of 950 MHz, and 3072 MB of GDDR5 RAM running at 1500 MHz through a 384-bit bus. It also is made up of 2048 Stream Processors, 128 Texture Address Units, and 32 ROPs.

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

Theoretically speaking, the Radeon HD 7990 will be 900% quicker than the Radeon HD 3870 512MB overall, due to its higher data rate. (explain)

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

Texel Rate

The Radeon HD 7990 will be much (more or less 1861%) better 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 should be a lot (about 390%) faster with regards to FSAA than the Radeon HD 3870 512MB, and capable of handling higher screen resolutions without losing too much performance. (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 (counted in megabytes per second) that can be moved past the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's 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 in one second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.

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