Help with computer parts and stuff

[joeybones]

So Ive been using Ableton for a while and I never had a problem with it and today I just keep getting cpu overloads and stuff.
Ive done stuff like this before and I never had a problem.
Some other programs are lagging as well

Specs
AMD Athlon II x3 450
4gb ram
Radeon HD5670 (pretty sure this doesnt really matter)

is it ok to mix ram? like 2 different companies?

 

[popatim]

Not usually due ti incompatible settings. The system will try to use the lowest speed to run them both but as you see it might not work right.