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476 Posts

05-03-2010

Italy

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  • Message 11 of 14

Re: Usable RAM stays at 2.75gb when upgrading from 3 to 4bg

2012-01-16, 14:29 PM

It really depends on the personal programs already installed.

Windows itself can be installed in 20 minutes or so, with very little human interaction (at the start and at the end of the process), the lenovo stuff can be installed almost automagically with thinkvantage updater.

Once I reinstalled my X200t while driving from Milan to Turin (about 160Km/100 miles) while driving.

 

I mean I started the windows installation before start driving, I launched the lenovo updater at the billing barrier, for the rest I watched the road, not the thinkpad.

If you have a lot of personal infos and programs the process is obviously longer.

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267 Posts

02-04-2008

Canada

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  • Message 12 of 14

Re: Usable RAM stays at 2.75gb when upgrading from 3 to 4bg

2012-01-16, 16:48 PM

XP and other 32-bit operating systems are limited to a maximum of 3GB physical memory. Your video claims 256MB for base operation, hence 2.75GB released for use by the operating system. The extra 1GB installed is redundant, neither used (nor seen by the OS) nor used by the onboard video.

 

Having said that, the exact amount of memory reserved for the video and OS will depend on the BIOS! Some board manufacturers, allow for full 3GB attribution to the OS in addition to allocating the correct amount of memory for video - hence, in your case having 4GB memory, some BIOS would read the proper amount (4GB), allocate the full 3GB limited by the OS and use 256MB of the 1GB extra by physical address extension, thus allocating that to video needs. Thus your system would read a total of 3.25GB RAM (physical address extension).  This was the case on my old X61. The X200 I had only read 2.75GB using Windows XP  (despite having 8GB installed).

 

If you upgraded to a 64bit operating system, the OS would make full use of the addtional 1GB RAM, thus having 3.75GB total usable.

 

0 person found this solution to be helpful.

This helped me too

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8 Posts

01-14-2012

DC

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  • Message 13 of 14

Re: Usable RAM stays at 2.75gb when upgrading from 3 to 4bg

2012-01-18, 10:52 AM
Many thanks - very helpful! Knowing this I will go back to 3gb since it does ot make a difference on my x100e,
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476 Posts

05-03-2010

Italy

5189 Signins

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  • Posts: 476
  • Registered: ‎05-03-2010
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  • Message 14 of 14

Re: Usable RAM stays at 2.75gb when upgrading from 3 to 4bg

2012-01-18, 14:44 PM

wrote:

XP and other 32-bit operating systems are limited to a maximum of 3GB physical memory.

 


Btw this is just the short answer.

Linux x86 with the large or huge memory memory support enabled can see more than 4 GB.

A lot of server versions of windows ,  can use more than 4GB of memory too.

And even XP with SP1 (not SP0/2/3) and the PAE support enabled can address more than 4GB.

Almost no one is aware of the latter example, because at the SP1 time almost no one had more than 2GB of memory, and almost no desktop user was aware of what the PAE was.

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