Which R9 290 card has best memory chips?

[houe]

Do we have any confirmation as which brands of R9 290(x) cards have good memory chips with large headroom for overclocking?

 

[chimaxi83]

They're all the same, either Elpida or Hynix. Each have been shown to overclock a decent amount, with both reaching 1700 MHz+ on stock voltage with reference cards. It's also been shown that there is little to zero benefit of overclocking past ~1500 MHz.