Can my PSU handle GTX 660?

Hitkliff Boss

Honorable
Apr 4, 2013
24
0
10,520
Hi, Iam looking for buying MSI gtx 660 twin frozr and Iam wondering if my PSU cna handle it.ITs this:
http://www.chieftec.eu/en/psus/smart-series/gps-500a8.html

CPU:
Phenom X4 965be - OC 3,8 ghz
4gb ram,
4 x 12 cm fans, 2 with red light
500 gb seagate hdd sata
MB: ga970a -d3
Thankk you.

Also I found this:
http://www.realhardtechx.com/index_archivos/Page873.htm
It says about my PSU, I think is manufacturer , isnt it?
It says this:
OEM - CWT. Does it mean that some firm CWT makes these psu and chefitec sells them?