Up to Eight (
PCI-E 6 + 2-Pin ConnectorsYet says: "4 x PCI-E" on the Specs tab
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207011
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From the pictures and their site, I think it's 4:
http://xfxforce.com/en-us/products/ts-series-full-wired/ts-series-850w-psu-core-edition-p1-850s-nlb9