HD 4830 Tweakers Delight or hobbled disapointment

Ok so with the NDA lifting in 2 days at last count, this is just for a bit of speculation and so i can get some questions off my chest.
The card is strongly rumoured to be a cut down 4850 but how much difference will going from 800SP's to 640 really make to it ? I'm expecting the clocks to be capped by the bios in order to keep performance down as by rights it should walk all over the 4670 and not be that far behind the 4850 at lower resolutions. The price point they are said to be aiming at, IE between the 4670 and 4850 doesn't in my opinion allow for price performance to come into it, the difference in the UK is £40 and with the 4830 for only £20 more. Well the 4670 would need to drop to make it viable.

What I'm really interested in is the architecture and if the disabled SP's can be Bios enabled or if they will be cut.
The back end will be interesting as well and another possible way to reduce its performance would be to cut down the number from 4 to 3 but that would give us a 192MB card wouldn't it ? People have been calling for a better ratio between the shaders and the back end since the 2000 series and if they keep it intact we could find out soon.

Thanks for reading
any comments welcome

Mactronix