What cpu should I buy to improve my solrate?
I have now celeron g1840 and my best rate is with -i 0,
with -i 1 is less and with -i 2 my rig freezes.
Higher "-i" have no impact even if I choose only one card with -di parameter :S
i have rx 480 rx 470 and r7 370
I have observed the same scenario and would also like to know the answer.
Will Pentium help? (I guess no, but maybe latest skylake?)
Will i3 be enough for 6, 7 card rigs, or we have to go i5?
I haven't heard anyone with an i3 complaining about 100% CPU usage, so an i3 is probably ok...i5 for sure. I would stick with haswell socket 1150 chips though so you don't have to spend extra on a board and ram...just drop it in!
280X's are becoming like say the highlander of the mining scene...
Any 290/390 mem straps modding easy to follow tutorial around? too bad there's no mem straps editor like polarisbioseditor for hawaii

Hawaii BIOS modding looks like a bit of a clusterfuck. I just modded my Gigabyte with Elpida ram, and it went from low 80s to high 80s. I also have two XFXs though with Hynix memory and they are already doing 95-100 without any mods. I'd like to try modding those too but I still have questions and I have been researching this for about a day now.
Only place I found any info though is here and it's not exactly straightforward:
http://www.overclock.net/t/1561372/hawaii-bios-editing-290-290x-295x2-390-390xThere are some premade BIOSes from the Stilt, but they are for reference cards only. I'm not sure if they are locked into specific core/mem speeds, or if you can still tweak with afterburner after flashing. It's not very clear.
http://www.overclock.net/t/1561904/mlu-bios-builds-for-290x