Your Sager system has more than enough power to handle PD.
Does your Task Manager show your CPU being maxed out when you try to do these edits in PD?
(Are you using the Trial version of PD or a 64bit fully registered version? the Trial versions are buggy.)
Try the following one at a time:
1.Try installing the latest PD beta patches to see if that will help. Look at the thread at the top of the page in this forum.
2. Disable your Nvidia 880M in the Device Manager and use only your Intel HD4600 to edit. Do you still get the lag?
Your main mSATA Crucial SSD should be fast enough
I personally prefer to use my single Samsung Evo 1 TB SSD as my main and video edit drive. C: partition on mine is 275GB while D: has the video files for editing and output. (Also make sure your Samsung Magician software is installed and RAPID mode is enabled in the settings.)
Other things to remember of course is to turn OFF indexing, auto formatting etc. since you are using SSDs.
Rob
PD 14 Ultimate Suite / Win10 Pro x64
1. Gigabyte Brix PRO / i7-4770R Intel Iris Pro 5200 / 16 GB / 1 TB SSD
2. Lenovo X230T / 8GB / Intel HD4000 + ViDock 4 Plus & ASUS Nvidia 660 Ti / Link: https://www.youtube.com/watch?v=ZIZw3GPwKMo&feature=youtu.be