I custom builtmy rig and even tho the gtx 570 maxes everything 1080p 60fps, i want somethin newer so i sold it for $120 (got for $100) and i am looking at the amd side as i have an amd 8320 processor, amd thermaltake case etc and i wanted to know if the r9 270x crossfire woupd be beneficial as i bought one a while back and my 570outperformed it in sk but nothing else. If i get 2 of the 270x's and dp a two-way crossfire would i see inprovement or is sk not multi-gpu suprtive? Cuz thrn i could just get a 280x. Prefer quick responses as i'll be buying this week.

Extra info: current psu is a high quality corsair tx650 meaning i can support high end gpus but only one so if i go the cfx route i'd need to sell this for $60 and buy an 850 for like around 100. If i go 280 i wouldnt need to buy new psu.
*shrugs*
Case is mid tower but has side bottom top front and rear vents and a gentle typhoon casenfan with 2 red led fans and a cpu corsair watercooler so i know heat and power constumption with crossfire is gonna be a thing to monitor just cuz my rig is currently in my room (i have a fridge in here too so i only have to leave for doorbell and washroom) but i dont want it to be a sauna :/ if anybody here knows which is the best route plz post why. And i am running sk 64bit via thrill's sk tweaking guide which can also be found on forums, tho i am not using the older jre runtime he recommended even tho other ppl had probs with the newer one, i am running it fine.