Advice on a new rig

[MiRai]

15% is all they were able to squeeze out in two year of technological advancement? Disappointing. At least there is a 6 core option now which will give me some kind of performance increase I expect.

When the competition doesn't offer any... competition, then what can you expect? AMD has been nowhere near Intel in terms of raw performance where it matters (for most people) for years now.

Think I'd be better of waiting for Broadwell?

If you're waiting for Broadwell with > 4 cores, you're probably going to be waiting until late 2015. The next 6/8-core CPUs are scheduled to hit later this year, but they'll be Haswell-E.

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.

The biggest difference is that I ran those clients at 1280x720 and you run your clients at 2560x1600. Not to mention that my 59 slave clients were running at a whopping 5 FPS. -_- It was only a test for fun and I would have needed much more available CPU to have gotten anymore FPS or resolution out of those game clients.

1280x720x60 = 55,296,000 pixels
2560x1600x15 = 61,440,000 pixels
1920x1080x15 = 31,104,000 pixels (for comparison)

With such a large resolution your hardware needs to work almost twice as hard (theoretically estimated) as someone who plays at 1080 -- Assuming both of you have identical video settings, framerate, etc.

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?

5 clients on a 2500K/4870 @ 2560x1600? I think that might be pushing it depending on the situation, but I could be wrong. It might be worth a shot, but I'd test it out before making the commitment and assuming it's going to perform well.