I think you might be comparing two different statistics. RAM and ROM.
I don't know how much ROM the device has (can be different, from 128MB/MiB to 512MB/MiB). This is your storage space to keep log files, routerOS versions, etc.
Then you have your RAM, it is the memory the device uses. You use it depending on what features are activated and how big certain tables are in your memory.
From what you are writing, all seems well and you have more then plenty of space left!
Well I cited the size of the flash because it was a "nice" number, namely 512MiB.
I was expecting the total (not free) amount of memory to be a similarly nice number. Looking in other
forum posts I find people with e.g. 128MiB total memory, which is also a nice round number.
In system/resources I find:
Free Memory 254.7 MiB
Total Memory 469.9 MiB
and for comparison
Free HDD Space 425.7 MiB
Total HDD Size 512.0 MiB
(so total hdd size is a nice number)
I hadn't looked at this until I was about to start graphing the free memory and the "total memory" value here seems odd. I initially thought maybe it doesn't include memory occupied by the boot image in that but as I said forum postings I've seen with "total memory" in them have round numbers (in binary at least).
If part of my RAM were defective I wouldn't have thought the thing would boot at all.
I am using spare RAM as web cache (I tried using microsd for that but the cpu went to 100%
and everything was unusably slow) so I expect to be using most of it for that most of the time.
http://routerboard.com/RB850Gx2
says:
Size of RAM 512 MB
Is everything ok with my 850? Why do other postings show round "total memory" values if so?
(My guess if my 850 is ok: different architecture for some reason counts total memory as that not occupied by boot image or some such thing)