Hardware Advice (Wotlk, 15 instances)

Hello all i'm looking for advice regarding hardware to multibox 15 instances of WoW(wrath of the Lich king patch 3.3.5). i'm trying to build a pc that can box 15 instances with main window at 60fps and slaves at 10-15fps(or better.). After a lot of reading my thoughts are this:

i7 5820k
MSI X99a raider mobo
msi radeon r9 390 8gb
32g ddr4 ram
500g ssd

my budget is ~1500usd however the lower the better
My questions are:
Do you think this proposed system could manage 15 boxing without sacrificing fps? (im not too picky on gfx like shadow detail and particle density for spells and such, however view distance is important to me)
regarding the gpu, should i opt for a higher speed gpu instead of more vram? (i have a limited understanding of the importance of the gpu in multiboxing, but as i've read about cpus more cores=better instead of faster speed=better and im assuming its the same in this instance? (quantity>quality?)
Apologies if these seem like stupid questions and thanks for your prompt reply =)
(and yes, i realize the ram is probably overkill but its so damn sexy :D)

We do not support private servers.

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