RAM, or random access memory, is your computer’s short-term memory. It stores the information that your computer needs to run programs and applications quickly and smoothly. RAM is faster than disks at reading and writing information, so the more RAM your computer has, the more it can do at the same time without slowing down.
But how much RAM do you need for your computer? That depends on what you use your computer for. If you mainly browse the web, work on documents, or stream videos online, you should have at least 4 GB of RAM. This amount of RAM will allow your computer to run most tasks without any problems. However, if you want to keep your computer running well in the long term, you might want to upgrade to 8 GB of RAM. This will give your computer more space to handle multiple programs and tabs at once.
If you do more demanding tasks on your computer, such as photo and video editing or gaming, you might need more than 8 GB of RAM. These tasks require a lot of memory to process large files and graphics. For these tasks, you might want to consider 16 GB or more of RAM. This will ensure that your computer can handle these tasks without lagging or crashing.
But having enough RAM is not enough to make your computer run smoothly. You also need to know how Windows manages the memory on your computer. Windows uses several mechanisms to manage the memory on your computer, such as virtual address space, virtual memory functions, and memory allocation policies. Let’s review these mechanisms and see how they work.
What is virtual address space?
The virtual address space is the range of memory addresses that a process can use. A process is a program or an application that runs on your computer. Each process has its own virtual address space that is private and isolated from other processes. This means that one process cannot access or modify the memory of another process unless they share it. This protects one process from being damaged by another.
A virtual address does not reflect the actual location of an object in memory; instead, Windows uses a table for each process that converts virtual addresses into physical addresses. A physical address is the actual location of an object in memory. Windows performs this conversion every time a process accesses an object in memory.
The size of the virtual address space depends on whether your computer has a 32-bit or a 64-bit operating system. A 32-bit operating system can support up to 4 GB (2^32) of virtual address space for each process. A 64-bit operating system can support up to 16 TB (2^54) of virtual address space for each process.
The virtual address space is divided into two parts: one for user mode and one for kernel mode. User mode is where most processes run, such as applications and programs. Kernel mode is where Windows runs its core components, such as drivers and services. User mode has access to its own part of the virtual address space, but not to kernel mode’s part. Kernel mode has access to both parts of the virtual address space.
How does virtual memory work?
Virtual memory is a method that a process can use to modify or query the state of pages in its virtual address space. A page is a fixed-size block of memory that Windows uses to store objects in memory. The size of a page depends on whether your computer has a 32-bit or a 64-bit operating system. A 32-bit operating system uses pages of 4 KB each. A 64-bit operating system uses pages of 4 KB or 2 MB each.
A process can use virtual memory to perform various operations on its pages, such as:
Reserving: Reserving a range of virtual address space for a process. Reserving does not provide physical storage for the pages, but it prevents the range from being used by other processes. Reserving also does not affect the available address space for other processes.
Committing: Committing a range of reserved virtual address space for a process. Committing provides physical storage for the pages, either in RAM or in a file on disk called the page file. The page file is a space on your hard drive that Windows uses to store pages that are not in use or that are low in priority. Committing also reduces the available physical memory for other processes.
Freeing: Freeing a range of committed virtual address space for a process. Freeing releases the physical storage for the pages, either from RAM or from the page file. Freeing also increases the available physical memory for other processes.
Protecting: Protecting a range of committed virtual address space for a process. Protecting specifies the access rights for the pages, such as read-only, read-write, or execute. Protecting also enforces the access rights for the pages, preventing unauthorized access or modification.
Locking: Locking a range of committed virtual address space for a process. Locking ensures that the pages are kept in RAM and not moved to the page file. Locking also prevents the pages from being freed or decommitted by other processes.
What are memory allocation policies?
Memory allocation policies are rules that Windows uses to decide how to allocate physical memory to processes. Windows uses several memory allocation policies to optimize the performance and efficiency of memory management, such as:
Working set: The working set of a process is the set of pages that are currently in RAM and that are actively used by the process. Windows tries to keep the working set of each process as large as possible, but not larger than necessary. Windows also tries to balance the working set of each process with the working set of other processes, giving priority to foreground processes over background processes.
Page fault: A page fault occurs when a process tries to access a page that is not in its working set. This means that the page is either in the page file or not committed yet. When a page fault occurs, Windows has to locate the page and bring it into RAM, either from the page file or from another source. This operation takes time and can slow down the performance of the process. Windows tries to minimize the number of page faults by predicting which pages a process will need next and bringing them into RAM in advance.
Memory trimming: Memory trimming is a process that Windows uses to free up physical memory when it is low. Memory trimming reduces the working set of each process by moving some pages to the page file or freeing them entirely. Memory trimming also considers the priority and activity of each process, trimming less important or less active processes more than others.
Conclusion
RAM is an important component of your computer that affects its speed and performance. The amount of RAM you need depends on what you use your computer for, but you should have at least 4 GB of RAM for basic tasks and 8 GB or more for advanced tasks. However, having enough RAM is not enough; you also need to understand how Windows manages the memory on your computer using mechanisms such as virtual address space, virtual memory, and memory allocation policies. These mechanisms help Windows optimize the performance and efficiency of memory management, but they also have some limitations and challenges. By learning more about these mechanisms, you can better troubleshoot and improve your computer’s memory usage and performance.