Maybe of interest to somebody. Here are my speeds, not peak but averaged over 1 day of running v2.1 with -I 2 setting. Interestingly no difference in the two RX 480s running on two different rigs.

Rig 1 - i7-6700k CPU with 1 GPU also mining with 7 threads, CPU usage is around 4% for the GPU miner exe.

• Sapphire Nitro+ RX 480 OC 4GB @ Stock settings (1306,1750) - 40.16 (Hynix memory)

Rig 2 - A10-5800K CPU with 2 GPUs also mining with 3 threads/cores, CPU usage is around 17% for the GPU miner exe.

• Sapphire Nitro+ RX 480 OC 4GB @ Stock settings (1306,1750) - 40.16 (Elpida memory)
• ASUS R9 380 2GB @ Stock settings (990,1375) - 32.64