I
read here that the 580X was a rebranded 580.
Specs on AMD page show the same thing:
https://www.amd.com/en/RX-series#paragraph-341606
Would be good to hear about the actual differences, overclock (to 100Mhz, as some have posted)...
The frequency of the GPU (base and boost) and the memory is reduced to use less power. Base and boost clock speed is ~ 150mhz less and memory is ~300mhz less with the Pro 580X vs RX 580 respectively.
This results in slower memory bandwidth (217 GB/s vs 256 GB/s) and lower RAW performance (5.5 Tflops vs 617 Tflops).
Polaris 20 (XTX), die size (232mm^2), process (14nm), memory size (8gb), shading units (2304), raster operation units (32), compute units (32), PCIe 3.0 x16, etc etc ALL the same between the Pro 580X and RX 580.
The Radeon Pro being IGP (integrated graphic processor) implemented (no display output ports, power connectors, etc) and TDP dialed back for thermals is why people categorize them as mobile GPU's. But they are both the same, saying the Pro 580X is a desktop GPU is just as accurate as saying the RX 580 is a mobile GPU, it just depends on their implementation.
The iMac uses Polaris 20 XTX and the MacBook Pro uses Polaris 21 XT. The 21 is pretty much the 20 divided in half. Half the memory bandwidth, half the compute, half the TDP, half the PCIe lanes, etc. So if we were looking for a mobile variant of Radeon Pro the Polaris 21 would be it.
BTW, AMD sells one GPU for every 10 products they market. AMD's product line is very convoluted to say the least but with Polaris and Vega the LOWER GPU's name the faster it is this runs at odds with the products name. Ex Radeon Pro Vega 48 uses Vega 10 and its a faster the Radeon Pro Vega 20 which uses Vega 12. And why is it the Radeon Pro Vega and not just higher numbers? The polaris wasn't the Radeon Pro Polaris....ugh