Radeon HD 3870 X2 1GB vs Radeon RX 580

Intro

Compare all of that to the Radeon RX 580, which makes use of a 14 nm design. AMD has clocked the core speed at 1257 MHz. The GDDR5 memory works at a frequency of 2000 MHz on this card. It features 2304 SPUs as well as 144 Texture Address Units and 32 Rasterization Operator Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

The Radeon RX 580 should theoretically perform quite a bit faster than the Radeon HD 3870 X2 1GB overall. (explain)

Radeon RX 580		262144 MB/sec
Radeon HD 3870 X2 1GB		144128 MB/sec
	Difference: 118016 (82%)

Texel Rate

The Radeon RX 580 should be quite a bit (more or less 586%) more effective at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)

Radeon RX 580		181008 Mtexels/sec
Radeon HD 3870 X2 1GB		26400 Mtexels/sec
	Difference: 154608 (586%)

Pixel Rate

If using lots of anti-aliasing is important to you, then the Radeon RX 580 is superior to the Radeon HD 3870 X2 1GB, by a large margin. (explain)

Radeon RX 580		40224 Mpixels/sec
Radeon HD 3870 X2 1GB		26400 Mpixels/sec
	Difference: 13824 (52%)

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 data (in units of megabytes per second) that can be moved past the external memory interface within a second. The number is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units 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 rate is also dependant on quite a few 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.