Reserved MFT Space Question

Very likely, this question has been asked before, but here goes again...

I have a relatively small system HDD (C:) ? about 75GB ? along with a 1TB external drive. The "used" space on my system drive is about 33GB, and approximately 42GB of "unused" space.

After running a Defraggler analysis, the map legend displays roughly 20%-25% of my system drive as "Reserved MFT Space." There are no files in this area ? it's just being "reserved.

Is this normal? It seems like a lot of space being reserved. Is this amount of space in any way being impacted by my external drive?

It's specially reserved for MFT, which means files will be written to that zone only after the rest of the drive has been filled. It doesn't really impact the performance to any tangible degree, as far as I know.

This is pretty normal. The external hard drive should have its own MFT zone as well, appropriately scaled.