First check the specs of your video card and see if it tells you a min wattage needed...usually on the newer cards it will say around 550 watt power supply needed, and since you're overclocking your CPU I would also suggest a better PSU. Add at least 100 watts to the min watt needed for the vid card and also check the amps on the 12 volt rails. For your PSU it's under the specs on new egg marked as Output. Your's says "+12V1@22A", with a newer video card...I would suggest an amp level of close to 30A. I've been building computers for years, and have found out the troubles with undersetting the wattage for the PSU.
For that kind of money you can do alot better, research alittle more at newegg.com, the corsair 750 is 89.00 after rebate ($10.00 less).
$99.00 is just too much for that power supply, 500 total watts and efficiency thats similar but about 40% less output watts available when needed.
Just doesn't add up!!
Efficiency is most productive when running 40-60 percent of PSU output typically.