So what was the original saying? As I see it, this phrase is wrong no matter how you look at it. Because all ram is used at all times, for example if you have 32GB of free ram, the kernel will use all of it as a page cache to speed up the file system. The more free ram you have the more files can be cached, avoiding access to the disk when you read them.
The original intent of this saying was different, but ya it’s been co-opted into something else
So what was the original saying? As I see it, this phrase is wrong no matter how you look at it. Because all ram is used at all times, for example if you have 32GB of free ram, the kernel will use all of it as a page cache to speed up the file system. The more free ram you have the more files can be cached, avoiding access to the disk when you read them.