What are these Performance issues ?
Personally I believe this is trying to get you to purchase the Paid version of Avast CleanUP.
I take it this happened after a Smart Scan ?
Even in the Avast Internet Security, there are modules a taster of other Avast paid products.
When you click Resolve, if this is for a paid product it opens a purchase screen do download the paid CleanUP module, it isn't actually going to resolve those issues.
Personally I'm against this type of promotion, give the person a headache and sell the aspirin. Whilst the reported issues may be correct I don't believe it should be done in this way.
Do you feel your system is any different than before, e.g. do you think you have a performance problem ?
If not you re unlikely to need it.