Radeon HD 3870 X2 1GB vs Radeon RX 580

Intro

Compare those specifications to the Radeon RX 580, which features a core clock frequency of 1257 MHz and a GDDR5 memory speed of 2000 MHz. It also makes use of a 256-bit memory bus, and makes use of a 14 nm design. It is comprised of 2304 SPUs, 144 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Theoretically speaking, the Radeon RX 580 should be 82% quicker than the Radeon HD 3870 X2 1GB in general, due to its higher data rate. (explain)

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

Texel Rate

The Radeon RX 580 will be much (more or less 586%) better at AF 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 running with high levels of AA is important to you, then the Radeon RX 580 is superior to the Radeon HD 3870 X2 1GB, and very much so. (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: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher 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 texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output 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.