Lets put it this way:

I was able to play FFXIV on a shitty laptop on a military base in the middle of Afghanistan (satellite internet) during 2.0.

Was I doing any high end raiding? Absolutely not. Titan Hard mode? Barely. I had to move 2-3 seconds BEFORE the mechanics happened.

What this did was make me get really good at memorizing the fights, and KNOWING the mechanics not simply reacting to them.