This is a good 1750 MHz strap for Sapphire Nitro+ RX580 8GB cards with Hynix memory from BuriedOne on Youtube.
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https://www.youtube.com/watch?v=uiPCwJV_ryMI copied it over the 2:1750, 2:2000 and 2:2250 timings on a Sapphire Nitro+ RX 580 8GB Special Edition (blue faceplate) and get ~29.25 MH/s ETH + 935 MH/s DCR with a core clock 1120 MHz, memory clock 2200 MHz, -96 mV undervolt and power limit -15% in Afterburner. Runs stable with no memory errors.
Turns out that Hynix strap from BuriedOne is the same one bundled with the new version 1.6 of PBE. LOL. The latest version of Polaris Bios Editor v1.6 from jaschaknack makes it simple to apply the right performance timings for your card. With the 'One click timing patch' option it will apply the bundled performance strap to the correct timings. I tried it with several brands of RX 570/580with Hynix, Elpidia and Samsung memory and they all now get 29 M/s+ stable. Much better than randomly copying timings from the diffrent straps. Some cards like the Sapphire Nitro+ have two diffrent sets of straps from diffrent brands of memory and PBE will corretly detect and apply the right strap to the right timing. Great update!