I have 2 different brand RX 480s
XFX GTR edition
Sapphire Nitro + OC edition
Both cards have the exact same Overclock at 1342Mhz on the core and 2100Mhz on the memory.
I've uninstalled/reinstalled drivers about 3 times now and I am consistently getting the same results. I opened up World of Warcraft (I've noticed this issue in 3D Mark Firestrike as well so it's not game dependent).
I used FRAPS to 'benchmark' and log frame times and logged my GPU Core Speed and Memory Speed using GPUZ while doing a consistent running path in World of Warcraft and noticed constant repetitive drops in FPS - happening almost always at the same interval.
After comparing the data I noticed my Sapphire card drops its memory Frequency to 300Mhz EVERY time the fps drop happens. This is not noticeable unless logging GPU stats every 0.1 second. I've attached a screenshot of this case and it repeats throughout the run. Meanwhile, my XFX card simply sits at max Memory speed and never drops.
How do I force my 2nd GPU to stay active during this short millisecond time-frame? Would this require a custom BIOS modification to memory timings or something?