XFX RX 470 Memory timing tuning and poor hash rate?

Hoping to get some help getting my hash rate up. A bit more info.

I am having a bit of trouble getting my 4GB RX 470s tuned I bought 6 cards total all from BestBuy "RX-470P4LDLR" 5 of them have Hynix memory and the other has Elpida. The strange thing is that I can get the Hynix cards to run at about 1925 Mhz with out screen artifacts or crashing but the Elpida at 1825. From what I have read the Elpida is supposed to be better.

Hynix = 1100 Mhz Core Clock | 1925 Mhz Mem Clock | Hash rate : 24.5 MH/s
Elpida = 1100 Mhz Core Clock | 1825 Mhz Mem Clock | Hash rate : 23.3 MH/s

What I have tried to so far

Using the 1500 Mhz timing for 1625, 1750, and 2000 on both cards with PolarsBiosEditor and ATIWinflash.
I have also tried the 1375 and 1425 timing in the same fashion.
I have also tried the timing from the Hynix in the card that has Elpida and got the same results. I was still unable to put the cards memory past 1825 Mhz.

I was hoping to get each carding running at least 26 MH/s stable as I have seem a lot of members posting 27 MH/s + for some 4GB cards.

Any advice on how to get some improvement please let me know.

Windows 10 Pro 64Bit
Non Relive AMD 16.11.5 Driver
Intel G3260
2Gb DDR 1333
H81 BTC Pro R 2.0