Adobe Premiere Pro CC 2015 very slow, lagging preview

Hello,

I'm currently facing a very frustrating issue in Adobe Premiere Pro CC 2015. I'm trying to edit 1080p, 30 fps footage with a bitrate of 20Mbps but editing it is impossible for me at the moment because Adobe Premiere is too slow.

I import the footage, and when I double click on the footage for it to show up in the "source" window, it just shows the "media pending" image/message. It takes minutes for the thumbnail to load, but even then I can't properly scroll through the video and figure out which parts I can use to put in the sequence. It only displays on frame from some part of the video and not the one at the marker that I move. Even if I cut out some arbitrary portion of the clip on put in a sequence (even though I can't tell what I'm working with), I get the "media pending" image again for the thumbnail in the "program" window. After a real thumbnail loads, I press play, but it doesn't even play the clip! The play button doesn't even always become the stop button. If I wait longer, only audio plays, but that single frame remains even though the marker runs to the right, meaning that the video should be being played. Pausing somewhere later, it takes minutes again to load a frame, a snapshot of where I paused.

System Specs:

OS: Windows 10, 64 bit

CPU: AMD FX-6300 at 3.5 Ghz

Graphics card: AMD R9-380

RAM: 2 x 4GB DDR3 in dual channel

Storage: 1TB SSHD, 7200 RPM

I've edited videos on less powerful machines without problems, so I can't image specs being the issue.

Any ideas of how I can fix this issue? Thanks in advance!

[Moved from generic Cloud/Setup forum to specific Program forum... Mod]