I thought from certain expectations the gt300 was about 40% faster than the gtx295... don't ask for a source its just in a couple threads i've seen "leaked" info on expected performance around 14000x score in vantage which is like 40% faster than the 295

ALSO

nvidia is meaning to release an x2 version of the gt300... whether it will in fact happen is unknown but I would count on it if its close to performance to the 5870 in performance... otherwise they have no performance offering thats competitive with a 5870 x2