OK. Thank you.

I used a PSU calculator on this website.. and I have entered in all my hardware info, and this is what it tells me....

http://i.imgur.com/9BiCd3y.png

It says that I only need 301 watts... and so, this looks good to me.

I do wonder though, if I'm going to be running the GPU all day, whether it's going to pull more watts than usual.

But otherwise, yes, I note your point that my PSU may not get what it claims.

However, the calculator gives me 50 watts to spare, so I'm probably OK.