I just got a new high end editing computer. It has a Nividia Geforce 3070 graphics card, an i9 10900KF processor, and 32 gig of ram. It's super fast and works great other than clips occasionally look glitchy when playing off the timeline. That same clip looks fine if I play it directly through media player or on my TV. I have updated the graphics card. Any suggestions or ideas?
A key to working efficiently is ensuring that your source footage settings (video compression type, frame size, frame rate, and scan method; and audio compression type, bit depth, and sample rate) are a good match for your edit settings and your main file export settings. Ideally, your edit settings also quickly convert to your delivery settings (if different from the main file settings). This applies to any NLE (Apple Final Cut Pro X, Blackmagic Design Davinci Resolves, Avid Media Composer, etc.).
What is the codec of the 'glitchy' clips? There's a good chance that is H.264/5 long-GOP media. Which is great for camera capture as specialized chips can create the stuff & write it to file quickly. It does this by mostly writing partial frames to disc.
But ... decoding it for playback, that's an entirely different story. The computer has to create up to 30 frames, a mix of frames typically both before and after the next frame, just to get the next frame ready for display.
Which is not a problem for intraframe codecs like ProRes, the DNx variants, and Cineform. Those codecs write every frame to disc as a discrete, complete frame. So if you're using an H.264/5 codec, well ... performance can at times be glitchy. I work for and with a lot of pro colorists, who have MASSIVE computers, and they all tend to transcode every bit of long-GOP a client sends to them before working the project. They hate working with the stuff.
You can't compare video players with NLEs by the way ... they aren't even close. A player puts no load on the system other than playing back one video stream.
An NLE is not ever just playing back a video stream. It builds a sequence on the timeline in metadata ... grabbing bits here & there as they come up on the sequence, applying effects to them. And because it is built to work a ton of effects at the same time, it's built to load a TON of itself into RAM./cache files, swapping out bits as needed.
So the playback occurs during a ton of other heavy-system-use workload.