Why can't I use the full 4 GB in the 64-bit version of Vista Premium?

CurlyWhirly

CurlyWhirly

CurlyWhirly

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I upgraded to the 64-bit version thinking that the problem where Vista only 'uses' aprox 3 GB (in my case it hasn't changed as it was 2.557 GB in the 32-bit version as well) would go away but alas after the upgrade, it hasn't made any difference :confused:

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I also can't understand why my graphics card has assigned 1 GB of system memory, this still leaves the 443 MB accounted for :confused:


Is this normal?

Thanks.
 
what motherboard do you have?

likely to be a bios setting, had the same thing on my media pc and work pc until i updated bios / changed the setting
 
bledd. said:
what motherboard do you have?
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Foxconn G31MX



bledd. said:
likely to be a bios setting, had the same thing on my media pc and work pc until i updated bios / changed the setting
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I had a quick look around the BIOS and couldn't see anything there :confused:

I saw an option DVMT/FIXED memory size but I only saw 2 memory settings - 64 MB and 128 MB so I don't think it's that as my graphics card assigns a GB of system RAM.

I googled it here

I'll have a look for an update of my BIOS but I don't really like doing this in case something goes wrong :(

Thanks for the advice.
 
So the issue isn't that you can't use the full 4GB, it's that 1GB of it has been portioned off to share with the graphics card. Which doesn't mean the system can't use it, merely that it is prioritised for use with the graphics card.

You can see from your picture that 0MB of system memory has been 'Dedicated'; eg committed exclusively.
 
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Fanatic said:
Should be something called "memory mapping" or MMIO, I think.
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No such option in the BIOS unless there's a hidden option somewhere like there was with my very old Gigabyte motherboard (GA-7VAXP)

The only options in the 'Advanced BIOS Features' are:

PCI Express root port function

System BIOS cacheable

Memory hole at 15 MB/16 MB (something to do with ISA expansion cards)

PEG/Onchip VGA control

Onchip frame buffer size

DVMT mode

DVMT/Fixed memory size

Init display first


Thanks.
 
platypus said:
So the issue isn't that you can't use the full 4GB, it's that 1GB of it has been portioned off to share with the graphics card.
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I don't know as I'm new to Vista as I've only been using it for just over a week :o

I also don't know if it's normal for the system memory to be used in this way?

Lastly, I don't know where the aprox 512 MB has gone as what's available to the O/S (2.557 GB) and the GB assigned to the graphics card only comes to 3.557 GB not 4 GB :confused:
 
CurlyWhirly said:
I don't know as I'm new to Vista as I've only been using it for just over a week :o

I also don't know if it's normal for the system memory to be used in this way?

Lastly, I don't know where the aprox 512 MB has gone as what's available to the O/S (2.557 GB) and the GB assigned to the graphics card only comes to 3.557 GB not 4 GB :confused:
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It won't be exactly 4GB, these things are never simple round numbers.

The issue is moot: Windows will use that memory if it needs to use it, otherwise it will keep it spare for graphics applications. If you disable Aero, and other intensive graphical options you will probably see this shared memory reduce.

Similarly, if Windows gets to the point where it is running out of memory (unlikely on a 4GB system), it will begin to shut down intensive graphic options that are loaded into this Shared pool in order to free that RAM up for the system.

It is indeed related to memory-mapped input/output (MMIO). Here is a KB article for you to peruse.
 
platypus said:
The issue is moot: Windows will use that memory if it needs to use it, otherwise it will keep it spare for graphics applications. If you disable Aero, and other intensive graphical options you will probably see this shared memory reduce.

Similarly, if Windows gets to the point where it is running out of memory (unlikely on a 4GB system), it will begin to shut down intensive graphic options that are loaded into this Shared pool in order to free that RAM up for the system.
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So the GB of RAM assigned to the graphics card isn't lost to the O/S then, it's just there in case it is needed?


platypus said:
It is indeed related to memory-mapped input/output (MMIO). Here is a KB article for you to peruse.
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Thanks, I'm reading the article as we speak :)



Slightly off topic but one thing I've noticed is that the way Vista handles free memory is very different from XP.

On XP, there was usually around 512 MB-1 GB of RAM free (I had 1.5 GB installed) but in Vista it is constantly close to zero and I think this is because the system caches more data and programs in an attempt to speed up Windows operations :confused:
 
CurlyWhirly said:
So the GB of RAM assigned to the graphics card isn't lost to the O/S then, it's just there in case it is needed?
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Yes.

Slightly off topic but one thing I've noticed is that the way Vista handles free memory is very different from XP.

On XP, there was usually around 512 MB-1 GB of RAM free (I had 1.5 GB installed) but in Vista it is constantly close to zero and I think this is because the system caches more data and programs in an attempt to speed up Windows operations :confused:
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Yes, the memory management in Vista is vastly different and much improved. In particular Superfetch, which prefetches frequently used programs into memory so that they load quicker. You can disable this, but there's no real need too as memory that is needed will be freed up anyway, and programs you use frequently..well..load quicker.

There is little point in having 4GB of ram with 1GB knocking about spare waiting for it to be used, much better to have an intelligent operating system manage that memory properly, and free RAM up as and when it is needed.
 
His Task Manager is reporting 2557 MB though. On a x64 machine with 4GB of physical memory this should be no less than 4000.

It looks like a hardware/BIOS issue to me.

The graphics card memory mapping is completely different in x64. The address space is so large that Windows can keep the mapping completely seperate from the mapping for RAM. Whereas in x32 the graphics card memory mapping would take priority over RAM mapping.

You should disable the feature where the graphics card is stealing that 1GB though. Presumably this can be done through the device drivers or maybe the BIOS.
 
NathanE said:
His Task Manager is reporting 2557 MB though. On a x64 machine with 4GB of physical memory this should be no less than 4000.
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I see.

Just a hunch, I have 2 x 2 GB memory sticks installed and I'm wondering if removing one of these temporarily would cause the BIOS to look at the memory settings in a different way i.e. even though I upgraded the O/S, perhaps the BIOS needs to be 'rebooted' so to speak?

Is this inadvisable as system memory would be halved?
Could it cause any problems even though it would be temporary?
I'd appreciate any feedback :)



NathanE said:
You should disable the feature where the graphics card is stealing that 1GB though. Presumably this can be done through the device drivers or maybe the BIOS.
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What do you mean by uisng the device drivers ???

I've checked in the NVIDIA Control Panel but can't see anything to do with shared memory and I can't find the setting in the BIOS unless there's a hidden menu somewhere?

By the way, I can't ask for technical support as I've overwritten the pre-installed version of Vista (32-bit) with my OEM version of Vista (64-bit) :(
 
you 100% sure you motherboard can handle that amount of memory?

for example i have a laptop which has a 64bit core2 set up with 4gb installed. however the bios will only register 3.2gb.

does all 4gb show up when it posts?
 
downloaded your manual, it says 'up to 4gb', but it probably doesn't support it..

i'd be tempted to get a P35 or P45 chipset
 
neil_g said:
does all 4gb show up when it posts?
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Yes it shows up when it posts, it shows up in the BIOS and from within Vista (below)


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p.s. I even tried taking out one of the sticks of RAM and booting it up without it and, as expected, 2 GB of system memory was showing.

I then turned it off and put the other memory stick back in and was hoping that this would 'kickstart' the BIOS but alas it hasn't worked and 2557 MB is still showing in Windows Task Manager :(

As has been mentioned on this thread, I think it's a BIOS setting somewhere :confused:
 
It could be that Vista's boot settings are telling it only to use 2557MB for some reason. Click the start button and run msconfig from the search box. Click on the 'boot' tab, then go into the advanced options and make sure that a maximum amount of memory is not specified.
 
I have a similar problem, Windows 7 reports around 3GB of available memory. This ties in with what my BIOS shows at boot up, when I enable memory mapping it will show in the bios as the full 4gb but with memory mapping enabled vista 64 refuses to startup it just hangs at the start screen even with everything at stock. What's going on there then?

I only appear to be getting 3 sticks usage at the moment..

Anyone?
 
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