Radeon HD 3870 1GB vs Radeon HD 7990

Intro

Compare those specifications to the Radeon HD 7990, which features a clock frequency of 950 MHz and a GDDR5 memory speed of 1500 MHz. It also makes use of a 384-bit bus, and makes use of a 28 nm design. It features 2048 SPUs, 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

Theoretically speaking, the Radeon HD 7990 should be a lot faster than 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 should be quite a bit (about 1861%) more effective 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 quite a bit (about 390%) more effective at AA than the Radeon HD 3870 1GB, and also will be capable of handling higher screen resolutions without slowing down too much. (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 information (in units of megabytes per second) that can be transferred over the external memory interface in one second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This number is calculated 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 card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill 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 reach the maximum fill rate.