best custom R9 290

The Sapphire Tri X or the MSI Gaming edition. The Tri X has slightly better temps, but the Gaming has a custom PCB and Hynix memory (ie it will overclock further) plus a backplate. It's also rumoured to be a little bit quieter.
 

Tests said the tri-x is actually quieter. Beside, after going away from stock r9 290 any card will sound silent.