Playback Glitch/Stutter with external drives

I've been using the same type OWC RAID 0 eSata drives for a couple of years and never had a problem before but in the last couple of weeks during playback on the timeline, not the source window, about every 4-6 minutes there's a stutter/glitch in the canvas window. The result is that the plasma attached to the Kona card loses sync.... so it's not something we can live with. I know it's related to using an external drive because when I transferred everything to a striped raid that I set up with internal drives in the MacPro, the problem vanishes. Everything has been checked. I upgraded the Sonnet E4p eSata card driver, I replace the E4p with a CalDigit eSata extender cable. No change. I tried different OWC RAIDS, including a Qx2, and it still happens. I don't think it would be RAM because it doesn't happen on the internal drives, but upgrading with an all new batch of RAM to 16gb is still a possibility. I have 8GB on an early 2008 MacPro model 3,1. All FCS and system software is the most recent and the Kona card has already been swapped out. Media is ProRes 422 LT 1280x720 23.98. Any suggestions on something else to try?

How full is the drive? This is something that changes over time and causes this issue. Sometimes just freeing up space by deleting old render files from old projects can help. Or have you been trying new drives?

Yeah, all new drives, two different ones just to be sure. All less than half full. It's just weird. And it sucks when something pops up right when you start a new project