Radeon Software and GPU-Z and Radeon Bios Editor report GDDR5 2000MHz on my RX590. However, speed is 256GB/s. According to datasheet of memory chip K4G80325FB-HC25 which is on my RX560, the memory timing is 0.25ns. 1/0.25ns = 4000MHz. At DDR, 2bit/clk * 4000MHz = 8GT/s. The datasheet specifies DDR at 8gbit/s per pin. (The Samsung chip/datasheet for my RX560 is more convenient to mention because it has that very explicit 0.25ns number. My RX590 uses Micron memory.) I downloaded several BIOS files from TechPowerUp BIOS Collection, they also report 2000MHz. Apparently all the tools/software are wrong? (QDR is a thing, but I have only seen DDR chips on my GPUs.)
Unrelated, but it would be cool if AMD published "datasheets" for their GPU chips. Maybe have a "Recommended Core Voltage vs Core Frequency" plot from like 1100MHz to 1600MHz or something like that. Would help quickly achieve a desired power rating when under-/over- volting/clocking.
P.S. I read online that BIOS mod is no longer possible on RX5700. I only use Windows to tune GPU, then RBE to flash, then move to Linux 100% (uninstall Windows, it's useless spyware other than some programs with lazy developers -- unless they got stuck with MS managed C++ or worse). Would it be possible to put unsigned tuning region in VBIOS? I know application better than GPU factory, especially considering case, airflow, performance needs... cooling solution is small part of the equation.
P.P.S.S. Any possibility of making a MEMTEST86 for GPU? Maybe using Linux kernel driver as a base? Or adding 9th chip for ECC? I really, REALLY hate fretting over "dead pixels" in memory chips........... my RX560 has some bad VRAM for sure, but has only crashed once in a few months, not too bad. Usually only see a few artifacts here and there.