Perhaps a mismatch between the clip and the sequence settings? Or maybe some effects on the clip?
I wonder if it's related to the problem I just fixed - after living with it for years!
I had problems with the CTI jumping back to the start of the sequence when rapidly jumping to the start of new clips and pressing play immediately.
It turned out that it was the configuration of my Shuttle Pro 2 - I was mapping the keyboard shortcuts SHIFT-UP and SHIFT-DOWN to two buttons. But there is an option in the shuttle config called smart release - I disabled this for both buttons and it now works as expected. Hurrah!
Maybe you could try disabling smart release for your buttons in the shuttle config and see if that helps at all?
Also - how have you got your shuttle config setup - does it struggle with using the jog wheel?
another thought - can you scrub the timeline by dragging the CTI with the mouse?
Nice one mate thats better, still doesnt kepp up with the footage completetly but it has improved it.
Its the jogwheel which is the problem or the scrolling of footage, I use the cs6 edit settings downloaded from the shuttle pro website.
I changed my shuttle settings to make the shuttling more responsive:
1 - 5 times second
2 - 10
3 - 15
4 - 30
5 - 45
6 - 60
7 - fast as possible
At least I changed this a long time ago - don't know if these are the defaults or not.
It'll only shuttle as fast as your system is responsive of course - so if you get instantaneous scrubbing by dragging the CTI in the timeline with the mouse, you should be able to get good performance with the shuttle. Of course that performance depends on the type of footage and how demanding it is on CPU to decode and whether youi have effects applied etc etc etc.
I edit pretty much exclusively with Sony XDCAM EX 1080P 25 footage we've shot on EX3 and PMW-350 etc and I get very very fast performance on the timeline - no issues at all i7 6 core 4GHz with 24Gb ram and fairly fast RAID array for footage.