X51 GTX560-ti PSU Requirement

Hi there

Just bought a nice X51 from eBay - i3 2020 - but unfortunately it arrived with a 240W PSU brick.

The reason why 'unfortunately' is because the GPU is a GTX560ti / Windows 8.

Consequently any stress placed on the card [ie gaming or running the Windows experience index] cuts the PSU and the machine out for half an hour.

I am sure that this config requires a 330W brick PSU, but going back to the dealer he says that Dell only recommended the 330W for the 555, and he's saying jsut return the machine at my own expense :-(

My question is thus:

Did Dell ever offer the GTX560ti as an option? I suspect that this machine with the GTX560ti might be a post-mod. Obviously, if they never installed it, they wouldn't have a recommendation of a 330W on their radar.