Paging+File+RAMdisk


 * Paging File RAMdisk **

//Myth// - "Putting the Paging File on a RAMdisk improves performance."

//Reality// - "Putting a Paging File in a RAM drive is a ridiculous idea in theory, and almost always a performance hit when tested under real-world workloads. You cannot do this unless you have plenty of RAM and if you have plenty of RAM, you aren't hitting your paging file very often in the first place! But thanks to the paging file in RAM, you will have more of them. Also: the system is ALREADY caching pages in memory. Pages lost from working sets are not written out to disk immediately (or at all if they weren't modified), and even after being written out to disk, are not assigned to another process immediately. They are kept on the modified and standby page lists, respectively. The memory access behaviour of most apps being what it is, you tend to access the same sets of pages over time... so if you access a page you lost from your working set recently, odds are its contents are still in memory, on one of those lists. So you do not have to go to disk for it. Committing RAM to a RAMdisk and putting a paging file on it makes fewer pages available for those lists, making that mechanism much less effective. And even for those page faults resolved to the RAMdisk paging file, you are still having to go through the disk drivers. You do not have to for page faults resolved on the standby or modified lists. Putting a paging file on a RAMdisk is a self-evidently absurd idea in theory, and actual measurement proves it to be a terrible idea in practice. Forget about it**."**