New cpu or overclock?

[kalvindeane]

Got a q6600 on 2nd comp at stock settings, I use it roughly 30% gaming and the rest for modding. I've got 2 5770's but I can only use 1 on this mobo. Should I buy a new mobo so I can use my 5770's in crossfire and then overclock my cpu, or buy an i5/i7 and overclock/hyperthread that? When I'm gaming, I am usually dual-boxing wow in raids or 4-5 boxing for farming. Will I see a performance increase in an overclocked i5/i7 over a q6600 for these uses? One more question, would I see a difference if I bought a SSD in my games and my modding? When multiboxing my framerate is only 10-30 in each window

 

[kalvindeane]

Corsair HX650w, 3gb of 667mhz ram. Btw just to show off, on my "better" rig, I can multibox 4 of my chars in raids >.<

 

[kalvindeane]

SIW tells me that I've got 2x 1gb and 2x 512mb. On a sidenote, if I overclock the q6600, what am I aiming to get? (noob at overclocking) and will I be ok with stock cooler or should I invest some money into a better cooler? Bearing in mind that I'll be using a Coolermaster CM-690 II Advanced Dominator Case for the rig soon