So I was playing around with Jukebox's ROM for Sapphire RX480 Nitro+OC 8GB

One of my video cards won't take the v4.rom (2150Mhz / 1750 straps) because it has shitty memory. (Even though GPU-Z says it has a quality ASIC, go figure...)
It wouldn't even reliably run the runner up: vdrop+.rom which is 2080Mhz / 1625 straps. (I think.)

The v4.rom showed failure right away, 0.000 Mh/s and crash.
The vdrop+.rom would start off fine, then slowly degrade to 26Mh/s and result in OpenCL GPU errors after about 30 minutes or less. Many reboots.
(I only achieved stability by WattTooling it down to stock 2000Mhz on boot before running Claymore.)

So after experimenting made my own version of the vdrop+.rom which works well as a third option for dumb cards.
All I did was modify the existing one from 2080Mhz to 2050Mhz and drop the memory voltage from 1000mv to 900mV.

This got me at least a 1.5Mh/s gain on the dumb card, it used to read 27.5 - 28.1Mh/s max, now it reaches 29.1Mh/s, very rarely touching 28Mh/s.

The whole rig is doing a total of 178-179 Mh/s-ish (I really wanted 180 damn) but I'll take it.
SC mining is also running at 2980 to 3030 Mh/s with %0.4 rejected shares which I attribute to the nicehash pool latency/design. (-dcri 17)