Processor Upgrade for Old B110

Hello,

I have an old and basic Dimension B110 with a Celeron 2.53 that I know I should really replace, but it is just not in the cards right now.  I have done a few things to it to try to help it keep up.  They are:

          2 GB Memory

          NVIDEA GeForce 6200

          WD MyBook ~320 GB 

I recently connected it to my 32" 1080 Samsung and most everything looks amazing.  But when I attempt to watch full screen streaming video from Hulu.com, the video becomes choppy.  So I figure the CPU is the next thing to upgrade.

 I am looking at:

          Pentium 4 3.0Ghz 512/800 Northwood SL6WK

          Pentium 4 3.4Ghz 1MB/800 Prescott SL7E6

So the questions are:

          Will both of these work with the B110?

          Comments on either?

          Is there something else I should upgrade, instead of or in addition to the CPU?

          Any other help in smoothing the video?

Thanks in advance for your help!