In my Dell XPS T550, I run a Celeron 1400 on a Lin-Lin FC-PGA2 adapter sitting atop a passive (no VRM) Asus slocket.
I set the jumpers on the Lin-Lin to request 1.4v, and the jumpers on the Asus slocket to passthrough the voltage request. The Dell/Intel motherboard seems more than happy to provide the 1.4v necessary for Tualatin CPUs.
The R450 is slightly older, but since your adapter has a built in VRM, it should work just fine--at least with Coppermine CPUs. Tualatin support will depend on the range of your adapter's VRM (can it get down to 1.5v?), and whether or not it will take FC-PGA2 chips.
94 MHz NEC VR4300 | SGI Reality CoPro | 8MB RDRAM | Each game gets its own SSD - nooice!