Then make your slide so it has each element of that equation you're teaching as a separate element to be introduced into the slide, instead of popping the whole equation at once, so you have to focus on each element. This isn't a matter of powerpoint being the problem, it's a matter of your usage being a problem. You go too fast; powerpoint isn't timed to go faster than you can speak. Click slower.
You still have the problem of the information on the ppt, no matter how granularly you organize it, is locked into a set order. Student questions don't come in any predictable order, so working with chalk provides you with the flexibility to incorporate questions naturally into your presentation.
Another problem inherent to ppt is macdinking. Sure, you can make every element of a complex diagaram or equation come up separately, but that requires fiddling with details. Even if you're extremely disciplined and efficient (which in my experience are not qualities promoted by ppt), it takes more time to do this explicitly in ppt than simply adding elements with chalk as you talk about them.
My students have never complained that my lectures go too slowly for them, and I make extensive use of the chalkboard. Even if the terms are already on the ppt (I use both together), writing it out as I talk about it provides visual emphasis. Some students are capable of scanning a ppt slide to learn a concept; others can learn very efficiently from the textbook; some need to hear me explain it, or see me sketch it out. My job is to reach as many different students, each with a different learning style, as possible.