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Comment by qwerty456127 | Hacker News Reader

I wonder why this is not a commonly available and used thing.

I have always wanted to use more RAM chips than my CPUs/motherboards would support, put all the swap on RAM chips, probably also load the whole OS&apps system drive into RAM this way (hint for your board: add an SSD it would load from, single-time on turn-on) and only use a persistent storage drive for my actual data files.

Using more RAM instead of HDD/SSD always felt like a thing producing really great return in performance on investment in money as RAM is relatively cheap and really fast. The amount of RAM you were allowed to plug into a PC motherboard always felt like the most annoying limitation.

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> I have always wanted to use more RAM chips than my CPUs/motherboards would support, put all the swap on RAM chips, probably also load the whole OS&apps system drive into RAM this way (hint for your board: add an SSD it would load from, single-time on turn-on) and only use a persistent storage drive for my actual data files.

You could create a RAM disk post-boot and then copy apps into it or use it for a working directory.

But you'll be disappointed to discover that virtually nothing benefits from this compared to a modern SSD. Copying files will be faster, but that's about it.

Operating systems are already very good at caching data to RAM. Modern SSDs are fast enough to not be the bottleneck in most operations, from app loading to common productivity tasks.

Even when we all had slower HDDs in our systems, creating a ram disk wasn't a big enough improvement to warrant creating a ram disk for most tasks. I remember reading a lot of experiments where people made RAM disks to try to speed up their development workflows, only to discover that it made no different because storage wasn't the bottleneck.

> The amount of RAM you were allowed to plug into a PC motherboard always felt like the most annoying limitation

You could always get motherboards that took more RAM, just not ones that taking your typical gaming CPUs and RGB. Currently there are standard desktop-sized ATX motherboards that take 3TB of DDR5, and ATX boards that take 1TB of DDR4 have existed for years.

*if money is not an issue. High end desktop/server platforms often require less cost efficient Registered or Load-Reduced RAM.

How much do you need? I think you can put 8 TB now.

(And of course you get a lot better bandwidth and latency than hanging it off some IO attachment)

Why would you want to put swap on a physical disk that is effectively RAM? That seems like a very redundant solution since swap as a concept becomes irrelevant if both main memory and swap are both volatile and equally fast. At that point, just add more main memory. The kernel is designed explicitly under the assumption that the storage backing swap is orders of magnitude slower.

They clearly state the reason in the last sentence:

> The amount of RAM you were allowed to plug into a PC motherboard always felt like the most annoying limitation.

You can do something similar (without a LiPo) in software from Linux https://linuxhint.com/create-ramdisk-linux/

The limitations would be the system would need to have a battery backup.

Because of the price of buying this DDR4 RAM expansion disk for, say, 1TB capacity, it would be cheaper just to buy a proper server board that has 16+ RAM slots and run the RAM-Disk in software?

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