Performance of Powerbook 1.67 compared to MDD G4?

Hello,

I used to own a Power Mac G4 2003 dual 1.25 w/2MB L3 Cache and 2GB of memory.. I wanted to know if the MDD would be a lot snappier under Leopard compared to the 2005-2006 17 and 15 inch powerbook G4's? Reason I ask this is because I do sense some "slowness" on my powerbook G4 under Leopard, where as on my MDD 2003 from the past it was a lot snappier and faster.

Could the L3 be making the MDD faster than my PowerBook G4? I do know that the XPC7455B found in my dual MDD was a dual 1.25.

Why is the performance so much faster on the G4 MDD compared to the Powerbook G4? Here were the specs of my G4 MDD..

2003 MDD G4
Dual 1.25 w/2MB L3 Cache
PowerPC G4 (3.3)
2GB PC2700 DDR
ATI Radeon 9650 128MB video card
USB 2.0 Card
Copper heat sink, naturally..

I never had SATA, but my two hard drives were 500GB each, running 7200 RPM.

Certainly, the 1.67 XPC7447A is faster than the 2003 MDD, yes??
I know the PowerBook isn't expandable as the MDD G4 was, but just wanting to know why the MDD would be a lot snappier under Leopard compared to my PowerBook G4? Is there a way to speed things up to par with the MDD I used to have??? Faster hard drives? Right now, my PB G4 has a 100GB 5400 RPM drive.. I know there aren't any 7200 Rpm drives higher than 128GB.

Someone please explain to me.. is the G4 MDD w/L3 much faster than the 2005-2006 powerbook?