[thawkins]

what's the point of having a bunch of ram sitting around doing nothing, I would rather have a system that had zero free ram but managed its address space well, so that changing ram usage was painless. why pay good money to have hardware sitting idle?.

[Karunamon]

The same reason I refill my car's gas tank long before it hits zero; low/no resource problems range from irritating to catastrophic. Unused RAM isn't wasted, it's headroom.

[kaba0]

But you OS doesn’t have to find a petrol station it may not even be able to reach — it can just swap to SSD or the best - swap to RAM itself by compressing pages (zram on linux and mac does it as well). Empty RAM is seriously wasted unless it is some embedded system where you are managing memory and need some strange latency requirements.