My computer started lagging really bad, so I went through every component and updated all the drivers I could think of. I finally ran CPU Z and looked around to see if anything was funny. That's when i noticed the Clock section kept changing. The multiplier keeps dropping from 15 to 5 and will stay there for quite awhile then go back to 15 for 5 minutes. I have looked online for an answer, but have yet to find anything. If anyone has any suggestions please help.
Sounds like your CPU is overheating. What are your load and idle temperatures? Clean all dust from your system, especially from the heatsink. If that doesn't help, reseat the heatsink with new thermal compound.
Using Core Temp 0.99.5, it is saying that Core #0 is at 21 C and 28 C and Core #1 is at 24 C and 27 C. I replaced the heatsink and fan a couple of months ago, but I will redo it to see if this corrects the problem.
Although the multiplier should go down with cool n quiet, it switching back and forth due to load should not cause lagging or a performance drop. Unless by "lagging really bad" you were talking about the multiplier and not about the actual performance you were noticing.