A good sAM2+ mainboard is as much expensive as a good LGA775 mainboard. So, at stock settings Deneb and Yorkfield have similar performance/price ratio, with an insignificant advantage of the Deneb platform. But when it comes to OC, the P45 based LGA775 mainboards are cheaper than sAM2+ SB750 mainboards, so Yorkfield platfrom has a little advantage.

So, to the table Deneb only brings the option of an cheap upgrade with a (finally) decent CPU for those who have sAM2+/sAM2 system.