But then veg always seems to go slow
That's too hot unless you're supplementing co2. Not a big deal now, but during flower that will cause your buds to become airy. Even if you get RH up to 60-70% (purportedly ideal for veg) you'd have to get your co2 up to 1200+ ppm for 83 to be okay... Try to get down to 78. Good luck.
PS, as an after thought, take a look at your nutrients and schedule - if that low of an RH doesn't cause your plants to suck up a ton of water and fertilizer and then burn themselves, than I'd guess that you're running a pretty low (ie weak) dosage of nutes. And what kind of light?