Radeon HD 3870 X2 512MB vs Radeon RX 580

Intro

Compare that to the Radeon RX 580, which comes with clock speeds of 1257 MHz on the GPU, and 2000 MHz on the 8192 MB of GDDR5 memory. It features 2304 SPUs along with 144 TAUs and 32 ROPs.

Display Graphs

Hide Graphs

Power Usage and Theoretical Benchmarks

Memory Bandwidth

Performance-wise, the Radeon RX 580 should in theory be quite a bit 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 is much (more or less 586%) more effective at AF 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 will be much (more or less 52%) more effective at anti-aliasing than the Radeon HD 3870 X2 512MB, and also capable of handling higher screen resolutions better. (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 data (measured in megabytes 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. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This 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 in one second.

Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. 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 lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.