Substance Painter 2018 Using All VRAM on Both GPUs At The Same Time

[Saulkar]

Hello there. I am no stranger to Substance Painter (almost 500 hours in SP2) but something that I just noticed is that all of the VRAM on both of my GTX 1070s is used up. Normally the more intense the scene is the more VRAM is used up but here this is happening in scenes that are a fraction of the size of some that I had in SP2 (6 2-4K texture sets vs 20 4K texture sets). I was initially not too worried about this as some other software reserve all available VRAM before performing any operation (Redshift Renderer) but I have not witnessed this phenomenon in SP before, let alone in any other card besides the one explicitly driving the display.

I would assume that this is the reason 2018 is extremely sluggish and many operations take much longer than normal to complete besides the dubious question as to why it needs to use up all of VRAM on both cards at the exact same time.
I am very busy right nopw and am taking only a few minutes to ask this before I get back to work as I do not have the time to experiment in SP2 and retest some of my old scenes. If anyone has any solutions to offer I am all ears.

System Speccs:
HP z620
Windows 7x64 Pro SP1
2x Xeon 2680v2
32GB RAM (soon to be upgraded to 64)
2x Asus GTX 1070 Turbo
SATA III 512 SSD for O.S./Program Installation + SATA II SSD for Scene/Texture Files (there are only two SATA III ports in my computer the second is used for a Render/Simulation CACHE drive)

P.S. It seems to be perpetually generating thumbnails, could this be the issue? Anyways I am almost done with my current bout in SP2018, back to work in Maya.
P.P.S. No other GPU intensive programs are open at the same time I noticed this issue.

[Saulkar]

I just opened an old, larger project in SP 2017.3.3 and not only is it worlds faster and more responsive, it does not use up VRAM from more than one card (the display driver).

[Jerc]

Could you please attach a log file? and if you could send me the scene you used to test the performance, that would be greatly appreciated.

[Saulkar]

I just made a log file (how do I get it to you?) but the problematic scene I tested this on is 2GB and would easily take more than a day and a half to upload with my shoddy connection. I could spend a few days downloading GTA V without issue but uploading anything frequently drops my connection and tends to corrupt things. It is always fun when you spend 12 hours uploading a video to youtube only to get a non-descript error or have an uploaded photo album on dropbox turn into a bunch of 1KB empties.

Joy.

On the plus side the program recently stopped hogging all the VRAM and I cannot replicate the issue where both cards would be filled up. Further more, I believe that I actually figured out why it is so sluggish. It has to rebuild thumbnails for every single layer in my older projects that I open in it but it seems to get stuck unless I solo the individual texture sets and let them finish individually otherwise it sits there forever generating thumbnails. I let this finish on my largest file (11 gigs and 71 texture sets 1-8K (4K in viewport)) and everything seemed to work fine. I created a log file for this scene as well, just in case.