A shop in New Zealand got hold of some overclocked XFX cards and the top one will work at 670MHz core clock. Nvidia's reference speed for 8800GT is 600MHz, but XFX will have two cards, one clocked at 640MHz and the fastest one clocked at 670MHz.
A Geforce 8800GT won't go much over 700 when overclocked but XFX decided it is not safe to go over 670MHz. The card is branded as XFX xXx Edition Geforce 8800GT 512MB GDDR3 PCI-E 2.0 SLI Video and works with 670MHz core and 1950MHz memory, has 112 Shader units and uses GDDR3 memory and 256 bit memory interface.
The card costs about $490 NZ without VAT, which is about €260 + VAT. We can thank our reader codenamed "rakuza" for this nice catch. You can buy one here and there is also a picture of that card here.