This frees up space in RAM to load the new application. Among the primary benefits of virtual memory is its ability to handle twice as many addresses as main memory. You consent to our cookies if you continue to use our website. We also share information about your use of our site with our social media, advertising and analytics partners who may combine it with other information that you’ve provided to them or that they’ve collected from your use of their services. Basically, it maps virtual address space to physical address space (either on RAM or hardware device). Also, note that virtual memory is always slower than true physical memory. Your programs don’t know that they’re using virtual memory — Windows takes care of everything behind the scenes, so Photoshop thinks that you have 4GB of physical memory. Virtual memory is an address mapper. With virtual memory, what the computer can do is look at RAM for areas that have not been used recently and copy them onto the hard disk. If Windows were limited to using only your computer’s physical RAM (the memory modules you installed on your PC’s motherboard), you would be up a creek because Windows 8 requires a minimum of around 500MB of memory itself, and Photoshop takes a significant chunk of memory to run. Weird & Wacky, Copyright © 2020 HowStuffWorks, a division of InfoSpace Holdings, LLC, a System1 Company. Programs use virtual addresses to store instructions and data; when a program is executed, the virtual addresses are converted into actual memory addresses. How Virtual Memory Works on Your PC By Mark L. Chambers Pseudo-RAM called virtual memory actually exists on your hard drive rather than as memory modules on your motherboard. Modern operating systems (Windows 8/7/Vista/XP, Mac OS X, Unix, and Linux) all use the virtual memory trick to feed your applications the memory they need. This frees up space in RAM to load the new application. The OS will then set up 120 MB of virtual memory & will use a program called the virtual memory manager (VMM) to manage that 120 MB. What’s a computer to do? After all, that data has to be written to and read from your hard drive rather than from superfast memory modules. He uses his experience as a computer hardware technician to demystify the workings of PCs. Virtual memory, as its name suggests, doesn’t physically exist on a memory chip. To check how much space it has remaining, display your Desktop and click on the File Explorer icon on the taskbar, and then right-click on the drive you want to check and choose Properties.). It is created when a computer is running many processes at once and RAM is running low. As you can see, Windows turns to your hard drive for help. How to Create a System Restore Point to Safeguard Your…. Suppose that your PC has only 2GB of random access memory (RAM) installed, but you just ran Photoshop and demanded that it load two 500MB high-resolution digital images. How much is enough? Mark has written a variety of books including Build Your Own PC Do-It-Yourself For Dummies. But there’s currently only 50 MB of available physical memory stored on the RAM chips. Why has Germany blocked sales of the Samsung Galaxy Tab? We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. Real, or physical, memory exists on RAM chips inside the computer. And, don’t forget that you’d probably be running more than one application at a time. It is an optimization technique and is implemented by the operating system in order to give an application program the impression that it has more memory than actually exists. It uses software to consume more memory by using the HDD as temporary storage while MMUs translate virtual memory addresses to physical addresses via the CPU. It uses a portion of the empty space on your hard drive to temporarily hold the data that would otherwise be held in your computer’s memory. Let’s say that an OS needs 120 MB of memory in order to hold all the running programs. Modern operating systems (Windows 8/7/Vista/XP, Mac OS X, Unix, and Linux) all use the virtual memory trick to feed your applications the memory they need. Try to leave at least 25GB or 30GB free on the C: drive at all times. In this case, your hardworking silicon warrior uses 2GB of hard drive space, so the total memory available within Windows (using both 2GB of physical memory and 2GB of virtual memory) is now 4GB, providing more elbowroom to work with. Considering the size of today’s documents and the amount of RAM needed by memory-hungry mega-applications, your 2GB PC literally couldn’t do its job. When you run out of physical memory, the hard drive activity light on the front of your machine never seems to go out. PC techs call your computer’s use of virtual memory drive thrashing because Windows must continually write data to, read data from, and erase data from your hard drive. Specifically, the system can operate as if its total RAM resources were equal to the amount of physical RAM, plus the amount of virtual RAM. On top of all that, you’d be loading 1GB of data! A PC that runs out of hard drive space is a terrible thing to see; applications start to lock up, you might lose any changes you made to open files, and Windows begins displaying pitiful error messages begging you to close some of your open application windows (or even restart). Virtual memory is a section of volatile memory created temporarily on the storage drive. And yes, if you’re wondering, all that activity shortens the life of your hard drive over time. Information about the device's operating system, Information about other identifiers assigned to the device, The IP address from which the device accesses a client's website or mobile application, Information about the user's activity on that device, including web pages and mobile apps visited or used, Information about the geographic location of the device when it accesses a website or mobile application.