Radeon HD 3870 X2 512MB vs Radeon RX 580

Intro

Compare that to the Radeon RX 580, which comes with a clock speed of 1257 MHz and a GDDR5 memory speed of 2000 MHz. It also features a 256-bit bus, and makes use of a 14 nm design. It is made up of 2304 SPUs, 144 TAUs, and 32 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon RX 580 should theoretically be a lot superior to the Radeon HD 3870 X2 512MB overall. (explain)

Radeon RX 580		262144 MB/sec
Radeon HD 3870 X2 512MB		115200 MB/sec
	Difference: 146944 (128%)

Texel Rate

The Radeon RX 580 will be much (more or less 586%) faster with regards to texture filtering than the Radeon HD 3870 X2 512MB. (explain)

Radeon RX 580		181008 Mtexels/sec
Radeon HD 3870 X2 512MB		26400 Mtexels/sec
	Difference: 154608 (586%)

Pixel Rate

The Radeon RX 580 is a lot (approximately 52%) faster with regards to AA than the Radeon HD 3870 X2 512MB, and also capable of handling higher resolutions without slowing down too much. (explain)

Radeon RX 580		40224 Mpixels/sec
Radeon HD 3870 X2 512MB		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 max amount of information (measured in MB per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better 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 number of texture map elements (texels) that can be processed per second. This is worked out 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its 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 clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of 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.