Repeating the start of an earlier thread...

Under Ubuntu 16.04.3 LTS Gnome:
Playing back a 3 minute clip on the Linux machine generally stutters and never smooths out. The file is 1080p60 fps, with no added transitions, etc. It's just a straight video clip.

The machine has 6Gb memory, AMD Athlon II X4 635 Processor x 4 (straight from the machine's Details page), a 750 Gb HDD, and AMD Radeon R7 240 Series, 6617 (2Gb)

In addition to the stutter, it now takes several minutes (typically 5 minutes or more) for the cursor to move to a clicked-on position on the timeline. Since this didn't happen earlier, I'm at a loss to think of what I've changed. The machine is the same, the USB HDD is the same... All I can think of is I changed a Kdenlive setting and broke something. I have no idea what it might be. I'm baffled.

I tried this with a clip with two cross-dissolves. The delay happens anywhere in the footage, not just at the transitions.

Trying to play back from anywhere in the clip is back to the stuttering described earlier.

ARe your clips HD ? The settng that might have changed is enable proxies.

Yes, they're HD. I guess I'll have to use proxies.