sent of an email to him and he says gaming mostly, and some overclocking
Will he let you pay with Paypal? You only need his email address to do so and it will be for your protection if you are not able to go and see it working ok.
If the card is fine he should have no problem with Paypal.
When i sold mine the guy collected so i could let him see it working fine before he took it. It's up to you but i wouldn't want to see someone ripped off.