Newest update speed issue

I have a question / problem with latest version of premiere pro. I'm running a pretty powerful system consisting of
I7 -7820hk processor in turbo mode
M.2 ssd
16 gb of 2400 ram
Gtx1070 with 8gb of ram
I'm mostly editing 2.7k and 4k video shot with a dji Mavic pro drone. My issue is 2 fold, first if I apply a speed boost to any clip of more then 150% it stutters real bad in time line. This appears to be since the latest premiere pro update. My second issue is if I open the dragon center utility to watch the usage of hardware, the gpu does not appear to be in use while doing anything in premiere. It's usage never really goes above 2 or 3 %. I have tried every trick I could find on web but the gpu still  does not appear to be working in premiere pro. Any ideas ?