HELP: Previous <busy> : 0/4 meaning?

[LoneStrider]

I was attempting to use cheat engine in a game today, and when doing my searches, I kept coming across <busy> : 0, and <busy> : 4 under the Previous section of the search results. I think it was also causing cheat engine to slow down quite a bit. Does anyone have any info on this? I also think it might have been messing with my search results in cheat engine, making it so I couldn't find the addresses I was looking for.