Hello guys! I have been using this miner for a long time now, but I just cannot understand something:

17625:13:20:17.214: main GPUs: 1: 31.507 MH/s (1) 2: 31.487 MH/s (5) 3: 31.485 MH/s (2) 4: 31.484 MH/s (6) 5: 30.601 MH/s (1)
17625:13:20:17.415: main GPU1: 50C 48%, GPU2: 52C 58%, GPU3: 50C 47%, GPU4: 46C 49%, GPU5: 49C 39%

All of my cards are the same, with the same BIOS modifications and setups! Why are some generating more heat than the others? I have tried to read the log file, but it's just not giving any infromation about that.
In HWINFO all stats are the same.