Okay I did the test with full render. Min threads 4, max5. Results were 6 minutes 49 seconds. My setup is same as before. 3.4ghz quadcore etc..
edit: Obviosly you gotta take into account that my processor is overclocked and still it's like 20% faster. But for me I dont consider it to be a profitable choice since I'd had to change the whole setup to get it. Perhaps if I build a second rendering machine I'l deffinetly consider it. I haven't read how it overclocks but I think my current one has a bit potential left in it