Most hobby servo's have a max voltage of 6v. The 450 mA should be OK for testing the servo unloaded.

If you have it turning a platform with large weight/mass then you can easily exceed 1A. A rule of thumb, the closer you get to maxing out the capabilities of your power supply the more noise you will see, especially true with motors, which could lead to glitches. I usually don't go over 50%, if I use a 2A supply for example, I only pull 1A.

Also, decoupling caps are a MUST! use inductors when feeding motors power with custom H-bridges. Use 0.1uf caps to filter out high frequency spikes at the motor and on your power supply to the PIC.

Do a search online for good engineering practice guides for dealing with inductive loads. There are tons of things that will go wrong working with inductive loads, you can solve most of them with well placed caps and careful layout.

Nick