CPU Spikes/Dropouts when moving parts/notes in editors

As subject. This seems to occur no matter how heavy or light the project is and is reproducible across 2 systems I have, the only common factor being the soundcard, an EWS88D PCI, and the same project files. I am in the process of rebuilding my template files from scratch to eliminate a rogue VSTi or effect.

This, or anything like it, does not occur in any other program (Ableton, all NI Standalones, Reason, you name it) but Cubase.

The last computer had an Nvidia GTX650, C2D e6600 and 4 gig,
The next, built partly because I thought the issue was my system running out of steam, is an i7 4790K using the onboard HD4600 with 8 gig of RAM - a powerful setup that eats plugins.

Still, when I move or cut, or even use the scissors tool around notes or parts during playback, I get CPU spikes. At lower latencies like 128 samples, these are accompanied by the audio breaking up.

As stated above, I will continue troubleshooting from within Cubase, rebuilding my projects and eliminating VSTi issues, but as this issue is reproducible across two systems, I thought I would enter it here.