Blackmagic Forum

Hi all,

I'm a long-time professional user,

PC SPEC:
Ryzen 5950X
RTX4090
64GB RAM

One very-long-time resource issue that still bugs me is the "using 100% CPU to generate thumbnails and locking up or lagging the PC".

This issue occurs with Thumbnail and Filmstrip timeline views. Let's say you have 100 clips or what-have-you, quickly zoom out then zoom in again to a different part of the timeline, the fans spin up, all CPU cores max to 100% and as a result the mouse pointer lags half a second behind you and the whole machine is unresponsive. It seems worse with some codecs than others.

My suggestion is simple: put a resource cap on thumbnail generation, unless there has been no user input for a couple of seconds. Whatever that is, say 80% CPU max, just leave something so the PC doesn't lock up.

The computer needs SOME CPU left over in normal use to actually function properly.

As you can my spec is high, but because it's literally 100% CPU power used for this task while you're trying to work it presents a nagging problem.

The current solution is to eliminate thumbnails by using "simple view", which is a shame, as thumbnails are nice to have.

color page -> lightbox -> wait while it populates

rinse and repete every time you open a project

the postage stamps seem to be pulled from the orignal source, if they are large (Helium i'm looking at you) or on a slow drive, it can take a while

i'm better off getting it over with once, than seeing it lag randomly though out a session

a workaround untill it gets fixed, i prolly noted this first around v11 / 2015-ish, so i'm not holding my breath

You can always right-click and choose "Update All Thumbnails" on the visible timeline. I think once you do that, the response time bouncing back and forth to different shots is pretty fast, even assuming 6K/8K source material (on a fast machine).

WORKAROUND

Since this post I thought of a workarounds in Windows:

• Task Manager
• Processes
• Drop down Resolve
• Right click Resolve and choose "got to details"
• Right click the Resolve.exe in details and click "set affinity"
• Here you can remove processor cores. I removed four of 32 threads, leaving four available at all times that Resolve cannot access.

This removes the lag entirely, as windows can use the spare cores.

************

many thanks for responses and tips. I've never used the Lightbox despite years of daily use so that's interesting!

I'm guessing it's not caching these thumbnails in case of file refreshing or alteration.

It's a shame as personally I'd prefer that thumbnails are just cached and only update when I ask, but hey I guess its a workaround for now!

I noticed the lightbox trick doesn't work for film strip view though, where the thumbnails changes for each zoom level, it's still locking up the machine without the CPU affinity workaround. Also Update thumbnails doesn't work for this situation, as the filmstrip thumbnails in the timeline are are dynamic and change with cuts etc.

The colour page thumbnails are also different as they include the current grade, whereas the timeline thumbnails show the log footage.

This probably wouldn't be so if my transform was applied at footage level but it's actually in the node tree.

The whole system would be fine though if it didn't use a full 100% processor and lock the machine up, for now in windows I'll have to simply remove Resolve's access to some CPU cores.