AMD R9 290X reference (HIS) photos
Capacitors - Samxon URL polymers, excelent stuff. See my avatar or some of my recaps:
I doubt that producers could come up with similar quality polymer caps, but we see. Definitively in the d10 dimensions, Samxon created back in 2008 even 470uF 16V caps, not need to downshoot to 330uF - the cap in my hands, 2008: http://trodas.wz.cz/kondiky/cap_images/1209896625.jpg
As far as 6 phases goes - if they can power a i7, then they can power an AMD R9 290X. It all depends on what quality the regulators are.
When the "phases wars" begin back in 2007, 2008 - we quickly discovered, that just to make "more phases", the companies used really shitty, outdated components (something like Creative using in X-Fi opamps from ~1970…) and just having a whole lot of them on the board does not mean anything.
As the output phase looks, 820uF 2.5V is the common size and capacity. There are existing ever 2700uF URL caps: http://trodas.wz.cz/kondiky/cap_images/1209896696.jpg
…but their ESR is higher, so they have lower maximum ripple current, and that is all it counts. I would employ there a Nichicon LE 820uF 2.5V cap with ripple 6600mA, currently used are 6100mA caps. Quite good, but the best Nichicons are capable od 6630mA - if the height 11.5mm is not a problem:
Nichicon R5 820uF d8x11.5
They did not skip on the ceramic caps single bit, witch is good. The two exmpty placer for big mosfets are interesting, never the less. Perhaps they should be powering something that is just not there? Dunno. Or maybe AMD is holding something back to add like a "XX" version? I have no idea. But clearly the design expected something to be there and it is just not
I like the board, tough it is not mine, lol ;D