POV-Ray : Newsgroups : povray.newusers : Problems with large RAM installed : Re: Problems with large RAM installed Server Time
10 Dec 2023 12:54:10 EST (-0500)
  Re: Problems with large RAM installed  
From: Le Forgeron
Date: 10 Feb 2020 13:00:56
Message: <5e419a58@news.povray.org>
Le 10/02/2020 à 16:25, Mirfaelltkeinerein a écrit :
> Hi all,
> I experienced a problem after upgrading a server from 1TB RAM to 2TB RAM (yes,
> really RAM) in our dual socket AMD EPYC machine with 48 cores/96 threads under
> Windows Server 2016. If I render a scene with 3500x1750 pixel, half of the cores
> are used (Windows processor group stuff) and the performance is quite nice. If I
> increase the resolution to 3600x1800 pixel (or more), it starts with 48
> threads/24 cores, but performance is bad and after several seconds, just one
> core/thread is doing all the work. Rendering can also not be stopped and runs
> till the end.
> I never experienced such a problem before. Do you have any ideas?

There is a default setting to replace "in-memory" picture in progress
with "on-disk" picture in progress when the memory needed for such
picture to render would be too large.

Obviously with 2TB of RAM (OMG!), you do not need such limitation. (it
is in place to save the innocents which cannot hold the picture in
progress in their small memory).

The setting is Max_Image_Buffer_Memory (default is 128 MB, using about
20 bytes per pixels, so check your size: first is 122 500 000, second is
129 600 000): you are crossing the boundary.



You can totally disable that security by setting the parameter to 0, but
do not cry when your process get swapped and the system crawls.

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