Large Timeline-C Disk 100% **SLOW**

Right now I'm editing a Wedding on my Custom Built PC. Its a beefy machine with...

i7 4790k Overclocked to 4.2ghz

32GB of RAM

480GB SSD Workdrive

GTX 1070

I'm in Premiere Pro 2017, and although I have a large timeline, I'm editing off an SSD, and the CPU doesn't seem to be working very hard, but the lag is THROUGH THE ROOF, with almost 10 seconds of delay between Mouse movements, and Premiere almost crashing!

The weirdest thing of all is the SSD doesn't seem to be touched, yet my C Drive (OS Drive) that Premiere is installed on seems to be jumping to 100% at times, and reading at sometimes as low as 0kbbps!

So my question is....is the SSD bad? What other options do I have to trouble shoot this...I have had this issue before, but with my machines power, it really shouldnt be acting up like this!