Ipad 2 on iOS 5: Should I update?

Hello everyone. I need some advice.

I have an iPad 2 on iOS 5.1.1. I've read about these devices on iOS 8 and their poor performance, which is why I never updated it since I have a youtube app and could browse without major issues. I don't use it for anything sensitive (like bank operations or anything that involves passwords) so I don't really mind security issues.

However, recently I've had more and more problems while browsing pages like wikipedia such as random errors appearing, pages not loading correctly and stuff like that. Needless to say, that never happened before but it's becoming more and more common. I'm not really sure if I should finally update it (Prefer it to be fast) or maybe use a specific app (with jailbreak I suppose) to boost its performance - what do you suggest?