We know it wont beat the 4850 in preice/performance ratio
Nvidia may have spoilt the party somewhat for ATI with the 9800+ GTX coming in at a similar price tag to the 4850. Also Looks like a better option than the ATI because of The Physics X and it seems to at least match or outperform the 4850.
Except that the 9800GTX+ isn't out yet, is slightly slower in most tests (close enough not to matter though), and the 4850 is already down to a pretty consistent $150-$160 after rebate. The cheapest 9800GTX on newegg right now goes for $175 after rebate, and most are still at $200. Keep in mind the GTX+ has a MSRP of $30 more than the GTX, and it isn't available yet either. Also, the 9800 needs a pair of PCI-E power plugs, while the 4850 needs only one.
Basically, it isn't an awesome card for the money, because it will be at least $50 more than the 4850 when it finally shows up, and certainly isn't available (much less easily available in any kind of volume) yet. As for PhysX? ATI is getting it too.
Here in the UK I've seen the 9800GTX+ going for £129inc VAT pre-order on one site. The gap in price between the 9800GTX+ and the ATI 4850 is pretty small then that's considering the Nvidia has Physics X on board. The review site I posted shows the 9800GTX+ and 4850 being neck and neck overall.
Doesn't ATI use something called havok for their physics? not physics X?
I probably wont be upgrading anytime soon, although I must admit it's mighty tempting with these prices. My 2900pro flashed to XT is still serving me well. My main problem I have with ATI is their drivers and this is one area I think nvidia is better at. I don't dislike ATI, but I've had better experiences with Nvidia.
Speedbird: Though there is no official support yet, the ATI 48xx series have been shown to be able to run PhysX, and Nvidia actually supports it. We'll have to see for sure, but I'd bet that they will have full support at some point not too far away.
Looks like it's possible to run Physics X on ATI, but AMD are not to keen so there's no guarantee of it being official. The 9800GTX+ for the time being ,saves the need for a separate physics X card and still performs similar in games, so for me it's the better card in that price range.