@Heyaz:

Firstly thanks for your very long and insightful reply.

Currently while ten boxing I have both tanks and both healers stacked on my center monitor at a resolution of 2560x1600 with two dxnothing windows on my side monitors so I can always see all four of them. The remaining six Dps chars are stacked on my top monitor at a resolution of 1680x900 with a small third dxnothing window below them so I can see what they're all doing, see screen-shot below. Like I said, all at the lowest setting and running them in DX9. Main char will do 15-20 fps depending on it's surrounding, the rest run a 10 fps.

So you're saying ten boxing will be possible with new hardware. 15, especially with WoD on the way, will be a no go on a single system.

I thought, after seeing MiRai's video where he walks his train through Stormwind with 60 chars on his new system, that 15 on a single machine should not be that much of a problem.

A second option might be to take my wife's old system, tweak that a little and use it as a second system. She currently has an Intel Core i5-2500K on a GigaByte GA-Z68AP-D3 mobo with 8 GB of ram and my old ATI Radeon HD 4870. What would be the best, not to costly upgrade, to get this system ready to play 5 chars?
Third option might be waiting for Broadwell to be released?

I will take an good look at all the addons I'm currently using, disabling, on a per toon basis, everything they don't really need.

Windows tweaking, running 8.1, haven't done any tweaking on yet. Will look into it.

So forget about a RAM-drive, just use two SSDs.

sP`!´Ke