I'm getting the impression that adding more RAM mostly reduces disk writes before the node is fully synced, not after.
Each new block requires verification, which includes reading and writing to
chainstate.
But I have extra RAM and I can bump it up to 16GB so I can give it a shot. The Celeron supports up to 64 GB of RAM
Usually the mainboard is the limiting factor.
With 16 GB RAM, that doesn't leave much for the rest of your OS. I'd go for no more than half your RAM, so try 8 GB
dbcache if you install 16 GB RAM.
Is that the only thing I need to change? Or are there other settings I should try too?
That should be enough. For what it's worth: my system has 16 GB RAM (and the mainboard can't handle more), and during IDB I increase
dbcache, but when normally running I reduce it to 1024 again. I don't want Bitcoin Core to occupy the majority of my RAM, I need it for other things.
I just checked: I've written 7.5 TB in the past year (I didn't do a new IBD on it). That's 21 GB written per day, for Bitcoin Core, swap and everything else running on my system. I keep
chainstate on this SSD, and blocks on my
HDD. At this rate, I'll reach my SSD's rated writes after 80 years.