Min recommend PSU is 450w, where that is a 650w, so yes it would run it. But it's probably worth typing your system info into one of those online power supply calculators to check that your other hardware isn't draining way too much power. In the case that it does use heaps of power, you might want something a little stronger. However, if you are using SLI which is two cards next to eachother I assume you will need 2x 450 (not 100% sure though).
I'll give you an answer: Yes, that is enough for two 9800GTX. However, I've never even heard of that brand, thus I recommend you to get a name brand (E.g. Corsair), or else you could suffer harch consequences (e.g. random system shutdowns, caused by the power supply's inability to deliver a constant (or not enough) to your motherboard's 12V.