tubing size?
 

ok here is my new rig.

P4 Intel base

DD TDX 1/2
M4 GPU block 1/2
Laing D4 pump
Black Ice Xtrme 2 radiator
Dual floppy reservior

1/2" fittings on everything

What Tubing can I use?

Can I use 1/2" ID 5/8" OD Tygon??

or 1/2" ID 3/4" OD Tygon???

R3605 tygon. model

I like the thinner wall bettter but with my pump combo pump says 50psi on it and the thinner Tygon is rated for 45psi. is this ok???

Can I use the 1/8" wall Tygon with the pump and blocks I have?

Yes, the thinner wall tubing will work. The 50 PSI rating means that the pump can withstand 50 PSI, not that the pump produces it.