Hello! Currently, I own a PC & Power Cooling 1200W PSU. It's a very efficient PSU, thing is, it's so darn loud and it's not modular. Is it a good trade if I switch this one with a Corsair HX1000 PSU? As of the moment, I don't know the pricing of my current PSU and if it's advisable to purchase a brand new one instead.
Today, a new PC & Power Cooling 1200W sells for $400.
You should be able to fetch a decent price for it on e-bay. My guess is $150-$200, but who really knows?
Some people value the absolute performance over any noise issue.
For sli GTX580, you will want about a 850w psu.
My suggestion is a Seasonic X series 850w or 1050w gold rated psu which will set you back $200 or so.
It is modular, and the gold efficiency means that the fans will hardly ever turn on.
Granted that's a 4 year old power supply which takes about 20-30% performance out of it according to power supply calculators. So i would say less than $120 you could sell it for since you can buy a better power supply with newer technology for cheaper than $250 from seasonic or corsair.