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I am wondering if I had made a mistake in buying 4 GB

By Ldxrunner ·
Salutations and Greetings Ladies and Gentlemen, I bought a laptop that has VBB 4 GB PC2-5300 667 MHz 2DIMM but the laptop is only reading 3 GB. I was led to believe that buying the extra gigabyte would enable me to get 64--bit software. Is this true ? Based on the informative and helpful reply from Palmetto, this may not be a good idea. Is their a use of the 4 gigabyte with SBB Intel Core 2DUO Process T 7800 with Microsoft Vista, 32bit, Ultimate ? I am also planning, by virtual install if that is correct, on using Linux. Thank you. Ldxrunner

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check the wbsite

by Dr Dij In reply to I am wondering if I had m ...

of the mfgr, detailed specs for the pc
what is the max memory you can put in?

if only 3g then won't see the rest.
I don't think would be an odd size like 3g, most are 4g or 8g max nowadays, but some systems use system memory for video in addition to video memory or exclusively system memory on cheap machines.

also if 4 sticks then one could be bad. I had this happen and one memory stick didn't show. I took the stick out and still same so knew it wasn't working.

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The Manufacture was Lenovo in the Far East

by Ldxrunner In reply to check the wbsite

Salutations and Greetings Dr. Dij, The laptop was manufactured by Lenovo in Singapore. The web site for Thinkpad T61 6459 with 15.4 WUXGA TFT. still lists 4 GB as the maximun memory. What do you now know that I should do to either get the machine to read the 64 bit or send it back and let them remove the extra bit, refunding me my money, and moving onto to the next subject ? Thank you.

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by normhaga In reply to I am wondering if I had m ...

you are using a 32 bit OS such as XP or Vista 32 then the most the OS will recognize is 3 gigs. This has to do with the limitations of how computers are built. A 32 bit OS can only use 2 gigs max. XP and Vista 32 do some tricks to allow that barrier to be exceeded.

Mathematically: 2^(32-1)-1 max memory for a 32 bit OS and (theoretically) 2^(64-1)-1 for a 64 bit OS.

If you do not have a 64 bit OS, then you are wasting money inserting more than 2 gig. If you have a 64 bit OS, then there are not yet a lot of "True" 64 bit apps out yet. MS estimates that it will be 5 years or more before "True" 64 bit apps are rolled out.

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No, his OS *shows* 3 GB, so he doesn't have the 2 gig limit.

by Absolutely In reply to IF

The "missing" 1 GB is allocated for system processes, but is being used.

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In responce...

by normhaga In reply to No, his OS *shows* 3 GB, ...

Did you read this sentence:

XP and Vista 32 do some tricks to allow that barrier to be exceeded.


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by Dr Dij In reply to In responce...

I saw a quad core 6600 intel pc (w/ xp or vista) advertized, looked up specs and at least one of them says 8gig max (tho comes with 4)

could it be 2 gigs per processor? or is the extra memory wasted?

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This all depends...

by normhaga In reply to Interesting

on the architecture of the motherboard and the CPU. I am not a fan of Intel and prefer AMD, so I cannot tell you specifics of the Intel.

Most likely, this is mis advertising in that while the MB can hold 8 gigs, the utilization of that ram is dependent on the OS used. A 64 bit OS would have no problem seeing and utilizing that amount or 8 times that (64 gig), but a 32 bit OS would have problems using that amount - unless each CPU had its own address space and was running its own copy of XP or Vista 32.

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I just bought 4 gig

by Dr Dij In reply to This all depends...

in a PC with a quad core. (intel).

PC specs - MB says it can hold 8 so I'd presume (possibly not correctly) that it could use all 8 gigs.

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Again, it depends...

by normhaga In reply to I just bought 4 gig

On the Motherboard and the OS.

If the MB has a 40 bit address/data path you can theoretically have 1^12 bits of ram. An mbyte is (1^6) * 8 bits. The rest just depends on the OS.

Before others correct me on this, this is one of the areas where things are not fixed and most often used is HD sales; some use a Kbyte as 1024 bytes and others 1 kbyte = 1^3 bytes. The error is mine in trying to simplify and doing this off the top of my head.

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You are slightly mistaken

by IC-IT In reply to IF

There is a 2 to the 0 equalling 1, however for memory you minus the 1 after the power because 0 is used as the lower bounds. Example 2 to the 8th and then minus 1 = 255 (but there are 256 including the 0). It does not mean 2 to the (8-1)-1 or 127.

The actual addressable memory on a 32bit OS 2 to the 32 = 4,294,967,296.
Traditionally this is used with 2GB available for applications and 2GB for the OS. The "trick" is in allocating 3GB for applications and 1 GB for the OS (actually 3Gb per process thread). Even then those applications must use Addressing Windows extensions.

Edited: here are a couple of nice links.

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