Is it worth it to upgrade the RAM on pr4100?


#1

I’m looking to upgrade my RAM from 4GB to 16GB in my pr4100. I use my NAS strictly for storing my media and serving to PLEX via Shield TV. I am looking for someone who has a similar setup and if the RAM upgrade made a big enough difference to justify the cost (about $100.00 US). Thank you!


#2

I bought 16GB for my PR4100 about a week ago, but I can not say that I see much difference in Plex to be honest. The main reason for me was to have enough RAM to be able to use ramdisk for Plex transcoding. It’s hard to say “how much good” it actually do, but more RAM = larger cache for files as well I guess.


#3

I wanted to run some VMs and FreeNAS on my PR4100, so I needed the RAM upgrade.
But for Plex and just a handful of users you won’t see any benefit.

You can use the ‘free’ command to see how much memory you’re using. If the swap is being used, you need more RAM. With htop you’ll see the disk IO and cpu are usually the bottleneck, not the memory.

An SSD in the first slot could make the whole box a bit snappier though.


#4

does plex even use the ram as a transcoding temp area as if i transcode i dont see any change in ram usage?

no where in plex does it let you choose transcoding location for ram :frowning:


#5

In PLEX, you can go into setting -> Transcoding. There, as the first first field; Transcoder temporary directory. When empty, PLEX is using a directory on disk, I think it was /mnt/HD/HD_a2/plex_conf/Plex Media Server/Cache/Transcode or something. I mounted some of my RAM as /ramdisk and put that there and as soon as you click [Save changes], the next time you start a new session it will use that directory instead.


#6

How do you mount some the ram on the pr4100?

Will have to give this a try :grin:


#7

You need to create a mount point (an empty directory), in this example /ramdisk
mkdir /ramdisk

then to mount 1G of RAM onto that mount point:
mount -t tmpfs -o size 1G tmpfs /ramdisk

This is not a permanent mount. I know there is a way to put this permanently in /etc/fstab but I haven’t done it yet. If you know how to safely do that, please share :slight_smile:


#8

But what do you gain with that ramdisk? It’s a fast cache for about 1 hour of transcoded video…
I only use transcoding for remote clients as I have limited upstream bandwidth. That same limited bandwidth reduces the need for a fast cache.
At home, you’d only use direct streaming as it uses less resources and you usually have the bandwidth available in the house.
You trade the huge capacity of pre-processed transcoded video for a faster cache that can hold only 1 hour… For video I’d rather take a slower huge cache than a fast tiny cache. It may make sense for audio but I doubt it.


#9

What I’ve experienced is that it’s the combination of media type and the client type (and if you’re using subs or not) that determines if transcoding is required or not. I’ve got lot’s of in-house clients that when running PLEX, could generate several transcoding sessions at the same time. That will be transcoding sessions not going on on disk, which I believe is a good thing. But then again, I haven’t had any problems regarding this before I upgraded the memory :slight_smile: I just decided to test this since I’ve got the RAM.


#10

Transcoding speed is limited by CPU power, not by disk speed. If you have many clients that require transcoding, you’ll rarely be able to serve them the cached processed video chunks as your cache is just a few GB in size (I estimate about 2 hours of video). If all your clients want to watch the same video, okay great… but otherwise you won’t have a lot of cache hits.

It’s like throwing a party with a super duper cooler that fits only 2 beers. You rather have a large fridge with plenty of cooled beverages (= cached transcoded video chunks).