Hello,
I have bought a second hand RB850Gx2 to play with and have as a backup device. One thing I noticed it only shows 352 MiB for total memory versus 512 MB in the spec sheet: https://mikrotik.com/product/RB850Gx2#fndtn-specifications
I can live with it if this is normal behavior as I will never use this much memory, but I’m worried something is faulty and may cause problems later on.
What other RB850Gx2 owners are seeing?
Thanks,
Adrian
If it’s actually showing that much memory (and it’s not the amount of free memory), then there is possibly something wrong with it. If it’s under warranty I would contact the seller.
I don’t know how popular these were. They were discontinued in 2018 I believe.
For ram it should show the correct amount. For disk, It could have been partitioned.
Mine shows 480MiB.
I could have sworn that it was 512MiB when I bought it. But I am not sure now…
It works perfectly fine nonetheless.
I’ve got two of them running 6.49.13 long-term and both of them are showing 480MiB. I was able to find screenshots of of RB850Gx2 on 6.33.3 showing 469.8MiB RAM available so it doesn’t always disappear in MiB quantities divisible by two. Maybe it’s just a Linux kernel quirk? On amd64 PCs running fairly modern Linux distros you’re never going to see exact amount of ram to the last byte.
So far my pair works fine too. I bought them used and sadly didn’t take screenshots to perpetuate how much RAM was available when I booted them first time.
Are we talking about RAM or storage size? Both are 512MB on this model.
Consider this print from one RB5009:
/system/resource/print
uptime: 6w4d7h18s
version: 7.14.3 (stable)
build-time: 2024-04-17 12:47:58
factory-software: 7.0.5
free-memory: 857.3MiB
total-memory: 1024.0MiB
cpu: ARM64
cpu-count: 4
cpu-frequency: 350MHz
cpu-load: 0%
free-hdd-space: 482.6MiB
total-hdd-space: 512.0MiB
write-sect-since-reboot: 357337
write-sect-total: 393386
bad-blocks: 0%
architecture-name: arm64
board-name: RB5009UG+S+
platform: MikroTik
“free-memory” is how much free RAM we have
“total-memory” is how much total RAM we have
“free-hdd-space” is how much free storage space we have
“total-hdd-space” is how much total storage space we have. This one is partitioned, this is why it shows 512MiB instead of 1024MiB
We’re talking explicitely about RAM. Here’s output from one of my 850s:
[ksx4system@orion] > sys reso pr
uptime: 4h14m59s
version: 6.49.13 (long-term)
build-time: Apr/04/2024 09:57:52
free-memory: 447.3MiB
total-memory: 480.0MiB
cpu: e500v2
cpu-count: 2
cpu-frequency: 533MHz
cpu-load: 0%
free-hdd-space: 432.9MiB
total-hdd-space: 512.0MiB
architecture-name: powerpc
board-name: RB850Gx2
platform: MikroTik
The other one reports exactly the same amout of RAM.
It’s weird this 480 MiB. The only thing that occurs me is thar some firmware/driver/BIOS uses some RAM, and keeps it from the SO. So, the router has 512MiB physically installed, but the OS can only use 480MiB. Because I can’t get a reasonably combination of RAM chips that could give 480MiB. Based on the site pictures, looks like it has 4 (or 8, if using both sides of the board) memory chips. If one of them failed, we would lose either 128MiB or 64MiB - and this is assuming the router would keep working.
It would leave us with either 448MiB or 384MiB of RAM.
Wait.
OP says the router reports 352MiB of RAM. You say it reports 480MiB.
512 - 480MiB = 32MiB missing memory
512 - 128MiB (one bad chip of four?) = 384MiB.
384MiB - 32MiB (the same “missing” from yours) = 352MiB.
So. How about this? The system uses 32MiB form some hardware or firmware. This leaves the SO with 480MiB.
Looking at the pictures, looks like it has 4 memory chips. So, 128MiB each, giving us the 512MiB total.
His router lost one of the chips. Completely. And it kept working with 3 of them - just like our computers sometimes do, when we get one loose RAM module, for example.
So, his router has (3 x 128MiB) - 32MiB = 352MiB. The math works.
How about it?
This seems to be true on fully functional hardware running relatively recent version of RouterOS v6.
I did some more research. More people reported only 352MiB of RAM available on other forums, all of them were using RouterOS v7. Is it just a weird coincidence (eg. one of four RAM chips failed for those people) or did we find a bug occuring only on this hardware? I’m probably going to try to source the third RB850Gx2 and netinstall it to 7.15.1 (or whatever will be the latest stable) to investigate further.
edit few days later:
RouterBOOT reports correct amount of RAM.
Board Info:
Board type: 850Gx2
Serial number: (censored)
Firmware version: 6.49.13
CPU frequency: 533 MHz
Memory size: 512 MiB
NAND size: 512 MiB
Build time: 2024-04-04 10:00:54