Installed memory ≠ usable size?


 
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Special Forums Hardware Filesystems, Disks and Memory Installed memory ≠ usable size?
# 8  
Old 07-07-2009
Quote:
Originally Posted by otheus
If you want to expand another gigabyte or so, you'll need PAE or a 64-bit OS.
I have a 64-bit OS! That was in my opening post.

Quote:
Originally Posted by otheus
You have only 4 GB of RAM installed. You can't get more RAM than what you have installed. If the OS sees 3.5 GB, it correctly sees how much is physically available to it.
When I had only 2 GB, it showed my RAM as 2048 MB. After adding 2 GB more, it shows 3584 MB rather than the expected 4096 MB.
# 9  
Old 07-07-2009
What is the "it" that shows 3584 MB?

The docs here says it can support 16 GB.
# 10  
Old 07-08-2009
Quote:
Originally Posted by otheus
What is the "it" that shows 3584 MB?
The BIOS, for one. gnome-system-monitor shows the same.
# 11  
Old 07-08-2009
Well, if the BIOS shows 3.5 GB, the problem might be the BIOS. Consider flashing a new BIOS. But first, I'd make sure the problem isn't graphics-card memory, which you haven't assured me it isn't.
# 12  
Old 07-09-2009
Quote:
Originally Posted by otheus
Well, if the BIOS shows 3.5 GB, the problem might be the BIOS. Consider flashing a new BIOS. But first, I'd make sure the problem isn't graphics-card memory, which you haven't assured me it isn't.
I imagine that I do that 512 MB of graphics card memory. But if I can address "64-bits" (actually most only handle only 48 bits at the moment) then this should not reduce the 4 GB.
# 13  
Old 07-09-2009
Quote:
But if I can address "64-bits" (actually most only handle only 48 bits at the moment) then this should not reduce the 4 GB.
Right. You were talking to the "Geek Squad" at BestBuy, werent you?
# 14  
Old 07-09-2009
Quote:
Originally Posted by otheus
Right. You were talking to the "Geek Squad" at BestBuy, werent you?
No, why would you say that? Smilie I bought the components for the computer at MicroCenter and assembled it myself. I haven't been to a BestBuy for ages.

I can't tell how you intended the statement since your intonation doesn't come through the text. Are you doubting my statement on 64-bit addressing? My understanding is that AMD64 systems set 16 memory bits (actually I think 16 of the middle bits, rather than just the 16 upper bits) to 1, limiting the actual space that can be accessed to 2^(64-16) = 2^48 = 64 terabytes. Let me try to Google up a source,

OK, I have one:
EmbeddedDeveloper.com - x86 - AMD64 (64-bit)
Actually this gives a limit of 48 bits of virtually-addressed memory and only 40 bits (1 terabyte) of physical memory.

Of course these are all better than Vista's 37 bits (128 GB for Vista Business), though I think that's an artificial restriction.
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