Suitable RAM amount

[txo]

Hello,

I'm going to dive into new 6200M camera class that produces whopping 120MB files per exposure. For that reason I started building new 16 core rig and I'm wondering what would be appropriate RAM amount. Will 32GB be enough or will PixInsight be able to utilize 64GB RAM?

thank you

[WillB]

The page linked below has the latest info regarding hardware and OS recommendations for PixInsight.

Max addressable RAM is 512GB, though whether your motherboard and OS can address 512GB is something else...

https://pixinsight.com/sysreq/index.html

[txo]

The page doesn't do any estimate as to appropriate memory size. It just says that min. recommended RAM is 32GB. And that is certainly not true. At the moment I process 20GB big 4k subs with just 16GB RAM and have absolutelly no problem.

[wvanreeven]

Well, it is a recommendation, not a practical limit, so it certainly is true. But it also says that PI can run with less memory. As a matter of fact, the minimum required amount of RAM, according to that page, is 8 GiB and the minimum reasonable amount is 16 GiB.


Wouter

[macbates]

Although you can get by with minimal RAM, increasing the size will make a big difference in performance. I just finished a running a WBPP script on 197 lights and 100 darks on a MacBook Pro with 16 GB of RAM. It ran fine, albeit slowly. Looking at the Activity Monitor, all 8 cores were at 100% utilization, but the important issue was memory. PI allocated 13 GB of memory (all that was available out of the 16 GB), but Activity Monitor showed thgt it was running with 53 GB of memory. All VM, of course, but that 'extra' 40 GB of virtual memory caused large amount of paging to the system disk. Even though it was an SSD, that's still a huge amount of overhead that made the WBPP script take a long time to complete.

On my MacBook I can't go beyond 16 GB, but in this instance (and many others), PI would have been much happier and completed in much less time if I would have had 64 GB of memory. Whether the cost of increasing memory is worth it is, of course, a different matter.

 - Ken

[stevek]

I would build it with 64G of RAM, without a shadow of a doubt.  I have 32G in mine and whilst it runs fine, I am mindful of getting a CMOS camera where the machine has to handle hundreds of 100Meg files in preprocessing.  Recall that if you use WBPP with SFS, CC and all the other options, it can take a while to munch through all that stuff. 

More memory will always be beneficial.

[txo]

Thank you guys. I'll go with 64GB. It's not that expensive anyway.

[hoxca]

The purpose of the RAM is to feed the CPU core.
In this era of multicore multithread CPU, why don't we specify memory / cpu core ?
eg: 4gb / cores seems to be the sweet spot ?

[Cosmic_Christopher]

I’m new to PI, but i rarely find the program utilizing more than 9.5gb RAM. However, it does pin my intel i7 8700k at 100% while running some processes