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.
P6 chip. Triple the speed of the Pentium.
Tualatin: PIII-S @ 1628MHz | QDI Advance 12T | 2GB DDR-310 | 6800GT | X-Fi | 500GB HDD | 3DMark01: 14,059
Dothan: PM @ 2.9GHz | MSI Speedster FA4 | 2GB DDR2-580 | GTX 750Ti | X-Fi | 500GB SSD | 3DMark01: 43,190