Anybody here have the same problem with me?

2 rig RX470 4GB, 1 Giga + 1 MSI. Same setting, same OC, same Hynix memory, same everything except brand, but different speed. Giga = 45 Sol, MSI = 35 Sol  

P/s: Those rigs was running ETH same speed. Giga = MSI = 25.2 MH/s