if your comp viewer is set to a different resolution than your preview resolution, it won't show you the cached preview on the timeline until they match.
Good thought but that wasn't it.
I achieve much better RAM preview lengths and render speed without the virtual cores.
That's good to know and I'll consider that just as a general performance thing.
After some more tests I was finding it working OK in another project but not my original one, and after a lot of reducing the original project I find that if you have done stabilization (AE Warp Stabilizer) within the project and it (Warp Stabilizer VFX effect) is enabled then this problem will occur - even if the Warp Stabilizer effect is not in the current comp (that's what fooled me the first time I tried to isolate it) - so it seems to be a bug that is an obscure conflict between Warp Stabilizer and RMFS PTR...
How big is your hard drive cache set? What kind of drive is it on? SSD or HDD? Also does it work as expected with RMFS turned off?
Yes this behavior (of losing PTR cache after a single PTR playback session) is specifically when using RMFS to do the PTR. If you turn off RMFS altogether or set RMFS to be render queue only then the PTR cache persists fine.
My boot drive is a 256gig SSD drive with 130gigs free and I had AE disk cache set to 60gigs of that drive. I just tried switching the cache drive to a 2TB HDD with nothing on it and increasing the cache size but it didn't avoid the problem. I have another SSD drive I'll be installing when I get a chance.
Here is what I think your problem is, your machine is starved for RAM - with dual hex CPUs that's 12 physical cores (or 24 virtual!!)
yes, the AE Mem&MP Pref panel shows 24 processor cores
chewing through RAM - I have a 3930K (single hex) and I had to upgrade to 64GB RAM to get decent preview length at full resolution in 1080p
but my problem is not (so far) with the duration of PTRs I'm getting, but rather that once the PTR is built (and the timeline shading indicates it is cached) it is gone as soon as I stop the initial PTR playback - once it shows as cached with green in the timeline it should be cached till something changes, right ? (shouldn't that always be true?)
couple things you can try:
- try lowering amount of RAM per core in MP settings (to 1 or 2 GB per)
- Try previewing at lower res (third or quarter)
in troubleshooting it I had already dropped to SD resolution (and even that at half rez) and had the RAM per core set at 2GB and then even 1 GB but the problem still happens
- turn OFF hyperthreading on your CPUS in the BIOS OR limit AE to use 6 or 12 CPUS in MP settings
I just set it to use 12, then only 4 CPUs by boosting the number of "CPUs reserved for other applications" in the AE MP prefs but it still loses PTR cache (BTW the only other app I've ever had running simultaneously with AE is Google Chrome but I did even try quitting that to see if it had anything to do with it but it didn't seem to)
- buy more ram. Honestly I would suggest 128 GB minimum for your setup
it's a possibility I'll be adding more RAM to this machine, but I'm unconvinced that the source of this particular problem is the amount of RAM installed (or RAM available when running AE)
Anyway, I DO appreciate your suggestions and would welcome any more ideas you or anyone else on this list has to offer.