Getting different hashrates for seemingly identical cards

I am pretty new to mining, and just doing some testing and optimizations, but I am stuck.

I have 2x RX480s: PowerColor RED DRAGON Radeon RX 480 and MSI Radeon RX 480, both at 4GB
https://www.newegg.com/Product/Product.aspx?Item=N82E16814131706
https://www.newegg.com/Product/Product.aspx?Item=N82E16814137082

They both have boosted core clock of 1266, they both have memory clock of 1750.

At stock running ethminer, I can get ~24.5mh/s from the PowerColor. For the MSI it barely cracks ~22mh/s.

I was able to get the MSI memory clock to 2000mhz stable using both Wattman and MSI Afterburner (separate tests), but the mh/s didn't budge. Infact, if I pushed it further, it seemed the mh/s seem to drop. If I do the same for the PowerColor, the mh/s goes up to almost 26mh/s.

I initially tried with pool mining, but setup thought that this might be an issue. I setup a geth node and solo mined, but that didn't seem to help either. The hashrate stayed constant.

The only difference I can find is that the PowerColor has Samsung memory and the MSI has Hynix. Would this be the issue? Is there anything I can do to remedy?

My end goal is to keep the memory clock stock but underclock the core clock and undervolt to save on heat/power/lifespan.

Any help would be appreciated!