Render times don’t make sense

[morgus]

So I have Vray next for 3-D studio Max and four rendered nodes. Everything seems to work great. Three render nodes are older HP workstations with duel Xeon chips and my workstation itself is an overclocked i7. The i7 is roughly twice as fast as the older HP workstations. In addition I just added a 32 core thread ripper render node and it is about three times as fast as my workstation and six times as fast as my other render notes. It all works as it should but I have a curious thing happening.
My animation has gotten into some frames that have a lot of transparency and shadows and it’s taking a lot longer per frame than usual. This is not unexpected, however, those usual relationships of computer speed are born out in render times for my frames usually, but now when it gets to a certain especially difficult frame all of the machines are rendering in roughly the same amount of time. So my super fast thread ripper and old nodes and workstation are each taking about four hours per frame. There’s a huge difference in their potential speed. On other frames that aren’t so cumbersome they have the expected relationship of roughly 1 to 3 to 6 time.

I am rendering using back burner network rendering, the setting is in buckets so there is no time limits, I’m using basically the default settings for render except for increasing the transparency to 1000, I know that seems excessive but I have a bunch of stacked transparencies like CAT scans that need this. That all works in other situations just fine and in fact it works here I just can’t understand how these machines with very different speeds, set in bucket mode, would render in the same amount of time roughly. As mentioned above, at other parts of this sequence when it is less cumbersome, like 40 minutes per frame, they revert back to the expected render time relationships that are very much in sync with their speed and with Vray benchmark for example.

using about 25g ram all boxes have 64

Please help me me understand what is going on.

Morgus

[morgus]

So my threadripper (32 core) is new and I am just now learning what it can do... I ran a sequence on network/backburner that is more typical and for some reason, my i7 10 core renders it at the same pace as the new 32 core thread ripper, both in about 35 minutes. Both show all cores working to 100% on each, both have plenty of memory for this scene, both on sshd, ... when I do vray benchmark the threadripper does 21 seconds and the i7 does the benchmark in 1:15 seconds. That makes sense. My actual render times, however, are not reflecting this.

what is gong on?

set to bucket, both renders look the same -

[Neilg]

Could it be because you are maxing out your network transfer speed while loading/unloading proxies and maps?

[morgus]

Well, the very same scene, but with less partial transparencies, doesn't behave in this fashion. There is one very big map and several "pretty big" maps.. but once the scene starts rendering I would think that they are all in memory and not moving through the network.... Ive got some experimenting to do and one thing will be to render locally on each machine and see if there is some issue with the network render process... thanks I'm going to investigate that..

[morgus]

So I made a simple scene just to test. Put all files on the machines locally so no network rendering. And my i7 10 core renders as fast or faster than my new threadripper 32 core. And once again, the vray benchmarks were repeated and they are consistently 21-22 threadripper, 1:15 i7; as expected.

Maddening.

[seandunderdale]

is the Threadripper the 1950 or the 2990?

[morgus]

2990
the scenes are all ones I’ve made. I’m going to experiment with one of the complicated environments I’ve bought, a detailed vr material operating room, today. Maybe something about my scenes that are problematic.

For evanple go to time 2;15 on thi demo video to see the types of models I’m using.
http://petercasanomd.com/ent3dnewmaterial.html

[morgus]

OK, so with an architectural scene, the treadripper is about 2x the i7. Not quite what it should be but makes more sense. Ill add in some of my models and materials and see if I can see what is the problem... Oh and I started to get lockups on the new machine, updated the graphics card and turned off overclocking and for now it is Ok.... Nothing is easy