Black Ops 3 launched on PC with some fairly serious issues, chief among them the fact it ran like stuttering garbage on i5 processors. A week later, is it safe to actually try and play the game if you'd previously been having problems? Probably.
I can't vouch for everyone's PC, and the millions of possible combinations and quirks native to the platform, but looking at forums — and my own experience — it seems the big, common issue (the leak that caused a swift decrease in framerate) making the game unplayable has been fixed.
I fired up the game's singleplayer campaign today and found that the gameplay experience was...flawless. A constant 60fps, even in the most chaotic and explosive sequences. This is in stark contrast to last week, when I couldn't even play for five minutes before the framerate dropped so low that I had to quit.
There's still weird stuttering in the game's cutscenes, but the actual in-engine content was 100% smooth. Now, if only the game had been this playable before Fallout 4 came out...