I picked up a new XFX RX 580 8G Black Edition (1405/2000) the other day and I'm trying to get used to it coming from a 7950. After running poclmembench https://github.com/kruzer/poclmembench/releases to test my new card's bandwidth I noticed something really strange - the speed of the last GB drops from 200GB/s to 5.20Gb/s. Does anyone know why I'm seeing this behavior? These are the only 2 instances of such a thing happening that I have been able to find: https://www.reddit.com/r/pcmasterrace/comments/arxlar/daily_simple_questions_thread_feb_18_2019/ This guy is seeing the exact same thing I am with a Sapphire card. https://www.overclock.net/forum/67-amd/1719214-powercolor-rx580-red-devil-7-0gb-1gb-vram.html This individual also went unanswered.