I'm not that thrilled by the SP aspects of NWN2, as it IMHO suffers from an overall clunky interface that detracts from the enjoyment of the game, just as the predecessor. NWN1 was however quite fun in Multiplayer with my gf, mainly because there are very few modern coop RPGs outside the MMO market. The problem is that our secondary PC is getting a bit old. The current specs are:

Athlon XP 2400+
1GB RAM
an AGP gfx card that wont run NWN2

Would this system but with a (AGP of course) 7600GS run NWN2 at an acceptable frame rate? We dont mind lowering the details.

The alternative would be something along the lines of oldblivion, but I havent heard of such a hack for NWN2...

You may get it to run, espacially if you go here to find some tweaks you can do, www.tweakguides.com .
There is a section just for NWN 2 that you can read up on to see how well it would work out. After that, it is up to you to say what is acceptable or not. The 2400+ and 1 GB RAM is really cutting it short.

With the right card, it might run it, with all the details turned off, as you have said. My system isn't much different than yours, except that I don't have the video card to support it. That's the only thing that kept me from running it, initially.

I think I'll just wait until our next PC purchase next year. I'd probably have to invest in better airflow and a new PSU if I upgraded the gfx card of that PC, and it'd end up a bit steep just for one game.

Do. You'll tear your hair out sacrificing settings in favor of playability and performance, all the while knowing that if you had a supported card you could play it as it should be. Get something nice though, not just the bare minumum and you'll be happy you waited.

I have the same system, except i have a ATI Radeon X850XT agp card (and a GF 6800 GT Golden Sample, havent decided which one to use..), would that make the game playable?