Running at 800 MHz GPU and 1000 MHz memory, Palit's GTX 460 Sonic Platinum is one of the highest clocked GTX 460 cards out there. It also comes with 1 GB of GDDR5 memory which can provide a performance boost over the 768 MB variants too. Being priced at reasonable $249 this card looks like a good alternative to a reference design purchase.

Palit GeForce GTX 460 Sonic Platinum 1 GB @ techPowerUp