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Why does a computer need a memory card if it has virtual memory?
Keep popularizing a little knowledge about virtual memory for everyone. As we mentioned in previous article, computer system can use hard disk space to simulate memory. At this time, some people will be curious: why do you need a memory card when computer has virtual memory?< /p>
Related literature: How much virtual memory should I install?
Let's look at the picture below
The figure above shows speed latency of a mechanical hard drive, solid state drive, memory, and processor cache, respectively. Since virtual memory is modeled with a hard drive, its speed is definitely not comparable to speed of real memory.
On a computer, all running programs must run in memory, which can be divided into physical memory and virtual memory. The size of physical memory depends on capacity of memory card. Since capacity of physical memory is relatively small, it is easy to get stuck. It is full of various applications and data. To solve this problem, WINDOWS uses virtual memory technology, that is, it uses part of hard disk space as "memory" to compensate for lack of computer RAM.
Virtual memory in Windows
The CPU will access memory frequently, it must have a fast enough read and write speed so as not to become a bottleneck in system performance. So how much is difference in speed between memory and "virtual memory" (i.e. hard drive)?
As an example, let's take a faster SSD whose memory accesses a lot of small data. Let's take 4K performance as an example:
SSD performance, its 4K read speed is 19.99MB/s
Next, model memory as a virtual hard disk. Below are the test data of DDR3 1600 memory:
Memory performance, 4K read speed is 1975MB/s
You can see that read and write performance of memory is more than a hundred times better than that of a hard disk drive (SSD), and more than a thousand times better when replaced with a mechanical hard drive. When your computer's memory is relatively small, you often feel stuck, main reason is that "Virtual Memory" is too slow.
Virtual memory is only a temporary solution. To ensure smooth and fast operation, size of physical memory must comply with standard. Due to limited daily applications of most people, 8-16GB of memory is basically enough. If you want to process large data such as video rendering, etc., amount of physical memory should be larger.
Isn't game of eating chicken very popular these days? This game has high memory requirements. There are many articles on Internet suggesting use of virtual memory for this task. Although this method has some effect, it is a temporary solution, not a permanent cure, because speed of hard drive is much less than speed of the memory.