Sampling Overlays

Just finished my first full track with GTP4 and have some questions regarding sample overlays.
 
I have bounced to track all of my guitar audio trax order to save computer processing speed. Also did the same with all of my drum trax. It all works great sound is wonderful and the CPU is untaxed. I also, do not have but four internal VST's working, so no bog down from that issue.
 
However, new problem arose. When I started dropping little audio bytes into a new track the CPU went nuts. Here is the scenario. I wanted to drop a small audio byte from a recorded newscast in a solo section of the track. So I used the loop explorer, dropped the audio byte in and truncated the front and back end to the preferred length. Keep in mind this audio byte was in .wav format. Then suddenly, latency bog down and I hate you from the CPU.
 
So my question is should the audio byte be in .mp3 format rather than .wav; or should I bounce it to clip to reduce the size. Probably a little bit of both I am sure, but want to get some feedback on best usage with little CPU bog down.
 
p.s. for those asking I have 2 GB of ram, running on dual core processor. Not the most over the top machine but never had an issue till now with any type of audio software.

Thanks Doc for the quick response. I read over a previous post you wrote regarding disc cleanup and the removal of background programs.

Good news. It helped tremendously. I should have tried that solution first, as I know better than to let that mess pile up. I am also going to try the ready boost feature with a flash drive I received. My guess is it wouldn't hurt.

You are correct about my system. Most of it is fairly standard material. However, I may look to upgrade in the future. But for now what I do is a 16 x 4 setup in GTP4 (more than enough for my usage). I record the guitar trax by direct input and use GR3 for amp simulation. Then I have found that if I bounce the guitar trax with the GR3 effect to a different track, I no longer need to have the GR3 effect open. Hence saving plenty of CPU usage.

Once again, thanks for all your help and I will be sure to let you know when I post our recordings.

Doc do I have a reason to get GPT4 since I have Sonar8 PE? I need something that can do prefabed loops for arranging and practice. Is GPT4 good for that?

Thank you so much Doc!