Why doesn t a 32 bit system recognize 4GB of RAM?

The problem is based on hardware limitations, memory size (i.e. the total addressing space of your system) = memory module (physical memory, e.g. your memory is 4GB) + BIOS memory + cache + video memory + .The addressing space of a 32-bit computer is 2 to the 32nd power, that is, about 4G, but the system allocates the 4GB address to the cache, video memory, hardware and other addressing spaces when there is a priority, the BIOS high-level mapping, the cache of each hardware, the temporary video memory of the graphics card, etc., their priority is higher than the physical memory you can use, so the system gives priority to the addressing space to the high-level mapping of the BIOS and the cache of the CPU and other caches of each hardware, the temporary video memory of the graphics card, and finally allocates the remaining addressing space to the physical memory you can use. Therefore, if you install a 4G memory module on a 32-bit computer, you can only use more than 3G memory module space, because the first few hundred MB of space is given to various hardware (including temporary access to video memory), so the 4GB memory module only has the addressing space, and you can only see the part of the memory that has been addressed.

If it's a 2G memory module, because the addressing ability of the computer itself is 4G, the first few hundred MB are given to the hardware, and there is still more than 3G addressing space left, and the 2G memory module can fully obtain 2G addressing space, and you can see the 2G memory, and to be honest, even if it is a 64-bit system4G memory, the real usability is only about that.

is addressing that is exactly equal to 4GB. However, for various buses, devices also need to assign addresses, and the memory can only have memory addresses, so that they can only identify the memory capacity equal to the address allocated to the memory.

Because the 32-bit x86 architecture means that the address bus of the personal computer is 32-bit, the CPU, memory controller, and operating system are all designed according to the 32-bit address bus.

It is important to clarify that 32-bit refers to the number of address buses of the CPU with 32, which is the so-called 32-bit. The concept of 32-bit in the operating system assumes that the number of address buses of the CPU is 32. In other words, both 32-bit and 64-bit operating systems assume that the number of address buses of the CPU is 32 bits or 64 bits.

What is the address bus for?An address bus is simply like an ID number, which is an address that uses a string of numbers to mark a stored bit. Just like the ID number, use a string of numbers to mark a person, even if someone else's town elder has the same name or other information as you, it doesn't matter, as long as the string of numbers is unique.

How does the address bus work?From the above description, we can see that the address bus is used to demarcate the position of a storage area, so how much position can 32 bits dedicate?In the computer operation, it is calculated in binary, that is to say, an address bus can only represent 0 and 1 two numbers, then, using permutations and combinations, 32 address buses can be combined to the 32nd power of 2, that is, 4294967296 numbers.

Generally speaking, the size of a storage is generally 1bit, that is to say, 4294967296 storage is a total of 4294967296bit space, that is, 4294967296 1024KB=4194304 1024MB=4GB. Speaking of which, you may be curious, obviously 32-bit can fully support 4G, why can the system only recognize it?This is because the 32 address buses are not all used to control the communication between the CPU and the memory, but also to control the communication between the CPU and the graphics card, the CPU and the hard disk and other devices, that is, if you join these devices, there are actually less than 32 address lines that can be used to control the communication between the CPU and the memory, which explains why the system cannot fully recognize the 4GB memory.

The fact that 32-bit systems cannot directly recognize the limitation of more than 4GB of memory is not simply on Windows PAE, but on the basis of the general logic of 32-bit.

The maximum memory addressing width of a 32-bit system is only 2 to the 32nd power, which is 4GB, which is the physical limit and is not something you can break through by cracking a piece of software. So why is the 4GB memory not directly recognized on the Windows system, but preserved by the early fiber shirt?The reason for this is that the hardware equipment of the system, her drivers, etc., need to occupy a part of the addressing width, and most of them are not all 4GB addressing width.

The so-called Ready for 4GB crack makes 32-bit Win7 equipped with 4G memory recognizable, but the actual vertical Li Ji is to let the system use this part of the reserved memory, the result is that the hardware device can not be divided into land cavities to the corresponding addressing width in the state of system memory full, resulting in system crash. Therefore, software such as Ready for 4GB should be used with caution. Even if you can identify the 4GB of RAM, it's impossible to run out of it, which has any impact on the performance of the system.

Bit operating system, with 32-bit CPU, addressing space bits 2 to the 32nd power, calculated to be.

4294967296 bytes, that is, 4G, 32-bit system supports up to 4G space, if you want 32-bit.

If the system supports more than 4G space, it is necessary to use PAE's special core to access it in a special way, but the system efficiency will be lower than that of the native 64-bit system.

Bit refers to the computer can have a 32-bit address line, so the total number of memory that can be identified (including memory and the output and input ports of various hardware) is a total of 2 to the 32nd power is 4G, but the computer also has to assign addresses to other hardware, so the memory that can be identified is only 3G, unless you install a 64-bit system. However, if you have 4G of memory, you should be able to install a 64-bit operating system.

3. If you want to identify 4G and above memory, it is recommended to install a 64-bit operating system.

1.What is addressing spaceAddressing space generally refers to the ability of the CPU to address memory. In layman's terms, it's a question of how much memory can be used.

2.We often hear that 32-bit operating systems can use up to 4GB of RAM. In most cases, this ceiling is not reached.

For example, my machine, although it is 4G physical memory, actually recognizes only 3G. Some friends said yes. Recognition or not, I don't think it has anything to do with character.

So, isn't the remaining 1 gigabyte or so of memory a waste? It's not, it's heart-wrenching. Everyone, many friends use a software to convert this part of the memory into a hard disk.

Note: I haven't used it myself, so if you want to try this feature, you need to be cautious. I heard from a friend that his Vista can turn on in 30 seconds and turn off in 5 seconds, and the speed is much faster when using it, especially for browsing the web. 3.

Why is it only addressable to this size? I'm going to explain it from a procedural point of view today, first of all, what is 32-bit? 32-bit is a term for CPUs, and for programmers, it means that the maximum number we can use when dealing with computers is 2 to the 32nd power.

How much is that? 4294967296 So what is this number in? bit, which can also be called a bit, or a bit.

This is something that computers can understand. There are only two values in this bit, which are 0 and 1, so how can this bit be converted to GB, it's very simple: divide it by 3 times in a row, and the result is equal to what?

Why 3 times? The first time to KB, the second to MB, and the third to GB. Hehe, the answer is exactly how big is the addressing space of a 64-bit CPU?

2 to the 64th power, 18466744073709551616......If I do the math, how many gigabytes can I get? 17179869184g

It's normal for a 32-bit operating system to only recognize memory, but a 64-bit operating system theoretically supports 2 to the 64th power.

You're going to ask Bill Gates about this.

1. Install a 32-bit or 64-bit system, the key is to look at the CPU model, if the CPU is 32-bit, then install the 32-bit system, if the CPU is 64-bit, then install the 64-bit system.

1) Open the "Run" dialog box, enter "msconfig", and enter the system settings.

2) Select "Advanced Options" under the "Bootstrapping" page box heading.

3) In the "Boot Advanced Options", remove the checkmark in front of "Number of Processors" and "Maximum Memory", and click "OK" to restart the computer.

32-bit systems are generally able to use up and down 3G of memory, and your display is available means that your computer is using an integrated graphics card, and part of the 3G is allocated to the integrated graphics card as video memory. If you want to fully use 4G memory, you can only install a 64-bit system, but because of your video memory, it probably shows that there is a little more available.

There is a personal patch upstairs that absolutely cannot be used and is useless, and if you want to identify 4G+ memory, you must install a 64-bit system.

This U-installed 64-bit system can be used to maximize its effectiveness.