http://www.futuremark.com/products/3dmark06/
Note the logo and "CPU performance testing via AI and physics workloads". It is also in various places during loading screens. Also, from the readme "AGEIA™ PhysX™ physics library by AGEIA".
I suppose though it could just be testing software physics, but I'd put bets that if you had the card you'd see a marked improvement for the CPU rating. That is, you know, if it ever becomes non vaporware. (Originally was reference boarded and ready to go for an Oct '05 release.)