I could take a look at your bios but as I see all other comments about more voltage in the 65288 positions place.
Basically you can't set higher voltage than 65288 basically because really you want to clock it to 65288 stable.
For my reference visiontek rx480 on 65288 is 1.250v, meaning 1250 in place of 65288 is the max I can boot the system at. Any higher set in that position, black screen upon windows.
I suppose the solution is "decrease" even further the vddci offset, though not ideal. Done in hex. To boot up higher.
To determine your 65288s max true real voltage, is try setting 1250 in place of 65288. Boot up, and don't set core clock too high. Something like 1415mhz up to 1466mhz works fine for me stock voltage.
If you think the card stock has +25mv then try 1275mv in place of 65288. I'll tell you if you can boot into windows on 1275 in place of 65288, then your GPU is very special.
If you need assistance, I can help but I didn't want to help if it's already been resolved.
By the way to answer what is safe max on these cards is no less than 900mv vddci offset value of -350 or -351 decimal to hex which is FE A1 flipped to A1 FE for reference. Which is 1250mv - 900mv vddci offset equals -350, in hex is -351 ie A1 FE. You can push the VDDCI offset up safely 100mv, to 1000mv vddci. Which if we kept the A1 FE value, new 65288 value of 1350mv - 350 (ie A1 FE) = 1000mv vddci offset.
That's a crazy amount of voltage for core but it's a known stable value while maintaining stock -351 decimal to hexadecimal value A1 FE. I would say that if this GPU can do easily 1400mhz on 1250mv stock 65288 and 900mv vddci offset. Then 1350mv on 1000mv vddci offset could yield as high as 1512Mhz.
To achieve 1563Mhz, mathematically it would call for 1395.53571mv on -351 ie A1 FE for VDDCI offset of 1045.53571mv VDDCI offset. Totally safe if taking extra special measures in the thermal department.
Dell Precision T7500 : Dual Xeon X5675 @ 3.536Ghz X 24 Threads : 48 Gigabytes : Cinebench R15 : 1505 : AMD R9 390X 8GB @ 1173Mhz 1350mv 57599 Power Limit @ 1250Mhz memory error free on tight timings / since 1500mhz+ had errors galore