When buying a new PC, should you spend the extra cash to upgrade your RAM? Here’s a rule-of-thumb for how much memory you need to run Windows Vista:
Windows Vista RAM
- 2 GB is minimum
- 3 GB if you can afford it
- 4 GB is mostly wasted
If a PC has 4 gigabytes (GB) of random-access memory (RAM) installed, Windows Vista will show significantly less than 4 GB available memory. For example, the Vista “System Information” dialog box may report 3,120 megabytes (MB) of memory available on a PC that has 4,096 MB (4 GB) of memory installed. Note this only applies to the 32-bit versions of Vista; the 64-bit versions of Vista can access between 8 and 128 GB of RAM.
To see how much memory you have available in Windows Vista:
- Double-click System in Control Panel, -or-
- Click Start, right-click Computer, and then click Properties
The missing RAM on a 4 GB system is “stolen” by various devices that require memory-mapped I/O (MMIO). Since a 32-bit operating system can only access 4 GB of address space, these devices are granted space starting from the 4 GB address and working backward. Devices include:
- BIOS, ACPI and legacy video support
- PCI bus for hard disks, sound cards, LAN cards, etc.
- PCI Express can consume 256-768 MB for the graphics card
So if a PC has 4 GB RAM installed, some of that 4 GB is used for MMIO. If a PC has only 3 GB RAM installed, the entire 3 GB will likely be available since MMIO typically uses memory above the 3 GB address.
The amount of missing RAM depends on the devices installed in the PC. But because of driver compatibility issues, the 32-bit versions of Vista limit available memory to 3.12 GB.
Links
- The 3GB-not-4GB RAM problem
- Microsoft: Memory reported in Vista is less than you expect if 4 GB of RAM is installed
February 9th, 2008 at 11:30 am
Windows Vista: 3GB or 4GB RAM?…
Interesting point at http://www.devtopics.com...
February 9th, 2008 at 11:31 am
[...] post by Timm Related ArticlesNo related [...]
February 9th, 2008 at 11:34 am
[...] Original post by Timm [...]
February 9th, 2008 at 11:45 am
[...] unknown wrote an interesting post today onHere’s a quick excerptIf a PC has 4 gigabytes (GB) of random-access memory (RAM) installed, Windows Vista will show significantly less than 4 GB available memory. For example, the Vista “System Information” dialog box may report 3120 megabytes (MB) of memory … [...]
February 10th, 2008 at 1:29 pm
I’v been using Vista just fine with 2 GB. Buy 3GB or more when the prices come down. :)
February 13th, 2008 at 4:30 pm
I bought a Vista machine late last year. Thankfully, I had a geek friend who told me not to bother with more than 3GB of RAM because Vista couldn’t handle more than that, so I only ordered 3GB. I always thought it was a little weird, so thanks for verifying for me!
March 12th, 2008 at 3:19 am
I read somewhere that Vista SP1 will address this problem with 32-bit Vista systems being unable to recognize 4GB of RAM.
May 3rd, 2008 at 6:10 pm
Hi guys
Got a Medion pc with quad core processor running 2GB RAM on Vista premium
Would like to upgrade to 4GB but read that anything above 3GB is a waste
The DIMMS currently in the machine are PC2-5300u-55-12E3 ( 2×1GB)
I have four slots can I use two PC2-6400u DIMMS in the other two slots?
May 8th, 2008 at 1:20 pm
I just installed additional 4 GB RAM in my Win Vista machine (32-bit Home Premium) and with the 2 GB it already had, it now shows me a total of 6 GB RAM. Shouldn’t it only show 3 (or 4)?
June 2nd, 2008 at 7:46 am
32 bit Vista SP1 changed the manner in which the available RAM is displayed. Now they show, the physical RAM available on the system & the RAM that is available to the OS. So what you are seeing now is the physical RAM, the OS is still seeing between 3-3.5GB.
July 23rd, 2008 at 10:19 am
i have 3.25gb of ram and vista runs smoothly!!
it boots in 15 secounds!
i have ultimate installed!
August 11th, 2008 at 3:16 am
yay you
August 13th, 2008 at 11:23 am
Actually in 32bit vista it does show the ram amount with sp1. However it still does not use all the amount of ram that’s available. This is due to the limitations of the 32bit architecture. What Sp1 does is merely show you what ram is installed on the system. 64bit computing is fast becoming mainstream as 32bit is now showing its age.
August 23rd, 2008 at 7:41 pm
Hi guys..
i m using windows vista 64 bit service pack 1 . i installed 4 gb of ram but its showing same as 3.12gb . So its not the matter of 32 bit or 64 bit , moreover service pack 1 didnt able to slove this problem. So if u guys a have any idea pls post or mail me at aks7sach@rediffmail.com
August 25th, 2008 at 9:07 am
Re: i m using windows vista 64 bit service pack 1 . i installed 4 gb of ram but its showing same as 3.12gb . So its not the matter of 32 bit or 64 bit , moreover service pack 1 didnt able to slove this problem.
Very strange! Almost sounds like you are still running 32-bit Vista. I’m running Vista x64 Pro SP1 on an HP laptop and it shows 4GB physical memory via “system information”.
September 27th, 2008 at 12:22 pm
Hi guys,
I bought a laptop with 4GB of RAM and on windows vista displays 3.1. But at the moment is displaying 4GB. Can i configure this manually? Dont know if it’s good but i noticed lower performance in games since then!
Thanks
October 6th, 2008 at 1:04 pm
Re :: hi timm …. Its not strange man . I m also with the Hp laptop with Windows vista 64 bit SP1 and ya its showing 4 Gb in system configuration but for your information if u wanna check how much your system exactly utilize your ram … type dxdiag.exe in search panel and check there ….. After upgrading to SP1 its fakely showing you 4 gb of ram but actually u able to utilize only 3.12 GB..
Gud luck……..
January 2nd, 2009 at 1:21 pm
Thank you for a simple explanation! I really appreciate you taking the time to just state things straightforward like that. You could give Dell lessons.
January 3rd, 2009 at 2:58 pm
Good post. I have seen it on my computer too. An increase of memory is always good and improves the performance of other computer or laptop!
As came to this site, I saw this website below which also deals with the subject!
http://bargainhere.net/laptop-memory/