Apple Users

But sometimes sites don't like it. If I'm not sure whether it's a Safari problem or another problem I try the site on Chrome.
Before I go to Chrome I clear history and empty caches. Sometimes that's all Safari needs to get moving again. Then I restart Safari and it's all fresh and new. I probably do that about four times a year.

I don't think the computer itself can affect how your browser works unless it's affecting a lot of other things, too. If everything is running slow, you might have a storage problem or other things that smarter people (or maybe a 4th grader?) can help you with but most of them are not expensive at all.