I am planning to get graphics card. I've been thinking about getting 4 GTX 660ti or 2 GTX 770. Other thing I want to fill up my motherboard PCie slots. 4 GTX 660ti my sound overkill but would the performance match with a single GTX 770?
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most games can't use more then 2 gpus in SLi/xfire. some few might be compatible with 3... pretty much none can work with 4. so... if you already have a 660ti, get a second.
You can't even put 660 Tis in quad-SLI. Max is 3. Also, the rule of diminishing returns means that the 4th card in any SLI/CFX setup is (mostly) wasted money.
IMHO, wait for better coolers on the R9 290 and grab two.