Ram

  • Thread starter Thread starter Jeff T
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Jeff said:
How do I find out how much Ram I've got?
Jeff
Click to expand...

There are two ways to answer this question.

One is, "how much RAM does my OS say there is".

And the other is "how much RAM is physically plugged into the computer".

On my machine, the answer to the first question is 3GB
and to the second is 4GB, and this has to do with the
way WinXP x32 works.

If I plugged in 8GB of RAM, the answer to the first
question would continue to be 3GB, as that's all that
Microsoft will let me use. In that case, I would be
wasting 5GB of RAM, as the OS won't let me use it
in the conventional way (for programs).

To answer the second question, there are a number of utilities,
but I like CPUZ. These are hardware inventory type utilities,
that report what is plugged in.

http://www.cpuid.com/softwares/cpu-z.html

(Zipped, no-install version. Unzip it, then run the cpuz.exe thing)

http://www.cpuid.com/downloads/cpu-z/1.60-32bits-en.zip

It will even allow you to "look" in each DIMM slot,
and see what is installed there. In this example, slot #1
has a 2GB DIMM. The pulldown menu for the slot, will contain
an entry for each slot present on the motherboard. On my
motherboard, there are two slot entries with 2GB in each
(Slot #1 and Slot #3), so then I know I have a total of
4GB plugged in.

http://www.cpuid.com/medias/images/en/softwares-cpuz-05.jpg

But when it comes time to determine "what the OS thinks",
the answer to that question is things like Control Panels,
System control panel, listed on the panel near the bottom.
And mine says 3GB in that case - as my OS is "wasting" the
other 1GB.

Paul
 
J. P. Gilliver (John) said:
Or

right-click on empty part of taskbar or Ctrl-Alt-Del
Task Manager
Performance

below the graphs you'll see Physical Memory

Both methods above will show physical memory available to the
processor, which might be installed RAM less video RAM if you have
on-board video that uses some of the main RAM.
Click to expand...

On my PC it shows 3406252 total, considerably less than the 4GB installed, and I
have no on-board video. I don't think on-board video is necessarily the issue.
 
On my PC it shows 3406252 total, considerably less than the 4GB installed, and I
have no on-board video. I don't think on-board video is necessarily the issue.
Click to expand...

If your Windows installation is 32-bit, then that amount of memory
sounds about right.
 
J. P. Gilliver (John) wrote:

On my PC it shows 3406252 total, considerably less than the 4GB installed, and I
have no on-board video. I don't think on-board video is necessarily the issue.
Click to expand...


No, it's not. All 32-bit client versions of Windows (not just
XP/Vista/7) have a 4GB address space (64-bit versions can use much
more). That's the theoretical upper limit beyond which you can not go.
But you can't use the entire address space. Even though you have a
4GB address space, you can only use *around* 3.1GB of RAM. That's
because some of that space is used by hardware and is not available to
the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's usually around
3.1GB.

Note that the hardware is using the address *space*, not the actual
RAM itself. If you have a greater amount of RAM, the rest of the RAM
goes unused because there is no address space to map it to.

Ken Blake, Microsoft MVP
 
No, it's not. All 32-bit client versions of Windows (not just
XP/Vista/7) have a 4GB address space (64-bit versions can use much
more). That's the theoretical upper limit beyond which you can not go.
But you can't use the entire address space. Even though you have a
4GB address space, you can only use *around* 3.1GB of RAM. That's
because some of that space is used by hardware and is not available to
the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but can
range from as little as 2GB to as much as 3.5GB. It's usually around
3.1GB.

Note that the hardware is using the address *space*, not the actual
RAM itself. If you have a greater amount of RAM, the rest of the RAM
goes unused because there is no address space to map it to.

Ken Blake, Microsoft MVP
Click to expand...

The RAM above 4GB *is* accessible, but from driver level. Only
the user space is restricted to a 4GB address space.
I didn't know that, until I ran into this product.

I installed 6GB of RAM on my WinXP x32 machine, and ran a ramdisk
software, and was able to use 2GB of memory I should not be able
to access. In fact, at the driver level, I could use up to 60GB
more for a ramdisk (as the driver level appears to have access to
PAE space). This is a benchmark of the ramdisk in action.

http://img196.imageshack.us/img196/8694/hdtunedataram2gbabove.gif

The ramdisk is here if you want to try it.

http://memory.dataram.com/products-and-services/software/ramdisk

Paul
 
Paul said:
The RAM above 4GB *is* accessible, but from driver level. Only
the user space is restricted to a 4GB address space.
I didn't know that, until I ran into this product.

I installed 6GB of RAM on my WinXP x32 machine, and ran a ramdisk
software, and was able to use 2GB of memory I should not be able
to access. In fact, at the driver level, I could use up to 60GB
more for a ramdisk (as the driver level appears to have access to
PAE space). This is a benchmark of the ramdisk in action.

http://img196.imageshack.us/img196/8694/hdtunedataram2gbabove.gif

The ramdisk is here if you want to try it.

http://memory.dataram.com/products-and-services/software/ramdisk
Click to expand...


Would this ramdisk work to speed up the swapfile?
 
Bob said:
Would this ramdisk work to speed up the swapfile?
Click to expand...

I tried that and it worked. When the system hits 3.5GB full, it
smoothly pages out without delay. And some of the other delays
I've seen on WinXP, disappear when that is used for paging.

The only problem is, it wasn't bug free when I tested it that
way. I had one instance, where a game errored out to the desktop
with no error message. And another error I saw, was an application
with no icon in the bar at the bottom of the screen. So there were
some rough edges and I had to discontinue the test. If you
use the ramdisk as Photoshop scratch, I'm sure you could have
plenty of fun with it that way. But I'm not 100% satisfied with it,
to use it for a pagefile.

I also don't remember the issues that would cause with hibernate.
I think my hiberfile stayed at the same size as usual, so the system
is assuming the ramdisk is persistent. And I didn't happen to run it
that way. I think you can set the ramdisk to be persistent, and write
itself out to disk, but I don't know if the timing is right for it
to work immediately at startup or not.

What I was looking for in my test, was whether the system would
outright crash or not. And it didn't. (When I tested that software
a year previous to this, it did crash my system.) I also wanted to
test whether it would behave well, when RAM below 4GB was full, and
it passed that test as well. But I didn't exercise the corner cases of
hibernation and the like. Since it failed to be 100% perfect while
testing, it's kinda a non-issue for me now.

I would trust the product for a Photoshop scratch disk though - or
scratch for some other application like that. One of the worst parts
of Photoshop in the past, was waiting for transfer to scratch to finish,
when working with large images. You could use your 32 bit OS, that
ramdisk software, and make yourself up to a 60GB ramdisk (assuming
the computer had room for 64GB worth of RAM). Some server motherboards
have room for that much, and 4GB DDR3 DIMMs are pretty cheap now.

Paul
 
Paul said:
I would trust the product for a Photoshop scratch disk though - or
scratch for some other application like that. One of the worst parts
of Photoshop in the past, was waiting for transfer to scratch to finish,
when working with large images. You could use your 32 bit OS, that
ramdisk software, and make yourself up to a 60GB ramdisk (assuming
the computer had room for 64GB worth of RAM). Some server motherboards
have room for that much, and 4GB DDR3 DIMMs are pretty cheap now.
Click to expand...

Paul, I have a question that I feel you're qualified to answer. :)

Do you think the PAE interface that is needed to do this trick is
present by default on new MoBo's? It's time to assemble a new desktop in
the near future, and I'd like to be able to use the RAM above 4GB as a
RAMdisk when I boot into 32-bit XP. But will the newer MoBo's
(especially since they're 64-bit), support PAE in 32-bit mode? If some
do and some don't, is there any way to tell which are which? The places
that sell MoBo's (like portatech.com, for example) don't mention such
details. If you know places that give more details, please mention them.

But please, don't go off on one of your extended researches - I don't
want to inconvenience you. :) Just mention whet you happen to know, and
your educated guess.
 
In
Paul said:
I tried that and it worked. When the system hits 3.5GB full, it
smoothly pages out without delay. And some of the other delays
I've seen on WinXP, disappear when that is used for paging.

The only problem is, it wasn't bug free when I tested it that
way. I had one instance, where a game errored out to the desktop
with no error message. And another error I saw, was an application
with no icon in the bar at the bottom of the screen. So there were
some rough edges and I had to discontinue the test...
Click to expand...

I use the freeware "gavotramdisk" that I believe is based on Microsoft's
RAMDisk. I don't know if it works passed the 4GB barrier or not. But I
can say I have never found one single flaw. Everything I ever tried with
it works flawlessly. Swapfiles, temps, etc. (don't put temps from an
install there that requires a reboot to finish, as it will be gone on a
reboot).

I don't think I ever used more than a 1GB RamDisk (this gavotramdisk can
handle up to 4GB). And there was something restrictive about saving the
RamDisk (so I don't use that feature either). I think it had to be FAT32
and no larger than 64MB or something. And I need a far larger RamDisk
than that.
 
Patok said:
Paul, I have a question that I feel you're qualified to answer. :)

Do you think the PAE interface that is needed to do this trick is
present by default on new MoBo's? It's time to assemble a new desktop in
the near future, and I'd like to be able to use the RAM above 4GB as a
RAMdisk when I boot into 32-bit XP. But will the newer MoBo's
(especially since they're 64-bit), support PAE in 32-bit mode? If some
do and some don't, is there any way to tell which are which? The places
that sell MoBo's (like portatech.com, for example) don't mention such
details. If you know places that give more details, please mention them.

But please, don't go off on one of your extended researches - I don't
want to inconvenience you. :) Just mention whet you happen to know, and
your educated guess.
Click to expand...

I don't think there'd be a problem there. The FSB is inside the processor now.

On AMD processors, I think PAE even stretches to 40 bits, and that's because
again, the FSB is inside. (Not that it's physically possible to put
that much memory on the processor - it's an architectural feature,
supported on both desktop and server, and might be more important
on a quad socket server motherboard with NUMA access to memory
located on another socket.)

There was a particularly bad Intel chipset design, where the connection
between the processor and Northbridge (i.e. an external FSB) was only 32 bit,
while the Northbridge could hold 8GB of RAM. In that case, the extra RAM
was simply inaccessible. The data sheet says to not bother filling the other
two slots, if you'd get a sum total of more than 4GB. So PAE on that one,
doesn't make sense. (Since PAE is also a call regarding the number of translation
stages in the page table, you can still enable PAE In that case. It
just doesn't achieve any user-visible improvements.)

There have been designs before that, where the FSB was 36 bit (supports PAE)
and yet, the chipset couldn't possibly hold 4GB of RAM. And then, when
Intel made a Northbridge with 8GB capability, they made the stupid
(marketing driven) move to limit the FSB to 32 bits. At the same time,
they made some (slightly more expensive) chipsets, where the necessary
36 bit address bus was present.

But anything you buy now, the memory controller is located on the
processor itself, which means the traditional FSB with 32/36/40 bit
address bus, is inside the processor. And with the RAM capacities
the processors have (16GB+), there really isn't a reason
to be playing those games any more. Even a laptop stripped down to
room for just two SODIMMs on the memory interface, can still hold
8GB.

Paul
 
BillW50 said:
In

I use the freeware "gavotramdisk" that I believe is based on Microsoft's
RAMDisk. I don't know if it works passed the 4GB barrier or not. But I
can say I have never found one single flaw. Everything I ever tried with
it works flawlessly. Swapfiles, temps, etc. (don't put temps from an
install there that requires a reboot to finish, as it will be gone on a
reboot).

I don't think I ever used more than a 1GB RamDisk (this gavotramdisk can
handle up to 4GB). And there was something restrictive about saving the
RamDisk (so I don't use that feature either). I think it had to be FAT32
and no larger than 64MB or something. And I need a far larger RamDisk
than that.
Click to expand...

The ramdisks based on the Microsoft sample code, all seemed to suck.
It seemed the developers who used that sample code, simply didn't want to
put the effort into extending the capacity properly. That link to the
ramdisk download I posted earlier, that's the first decent implementation
I've seen, and it took the developer a couple of years to get it where
it is today. They didn't come close to getting it right on the first
attempt. But it's now pretty good. The other ones I played with years
ago, the developers treated it like a ten minute project, dumping it
after the compile finished :-)

I've never heard of your "gavotramdisk" ramdisk. This is not something
I search for on a daily basis or anything. Just when the topic comes up
and there might be justification to use one. Now, what's interesting,
is when I look at pictures of it, I swear I've seen that somewhere
before... I can't remember where though. Almost as if the dataram ramdisk
might have looked like that at one time (same control panels?). The
control panels on the dataram one, have changed over time, so the
appearance today, isn't the same as it was at the beginning.

http://www.jensscheffler.de/using-gavotte-ramdisk-in-windows-7

http://memory.dataram.com/__documents/file/Dataram_User_Manual_35.pdf

Paul
 
Paul said:
I don't think there'd be a problem there. The FSB is inside the processor now.
Click to expand...

Thanks, Paul! That's what I thought too, but one never knows. I was
wary of them doing something in the vein of your example below,
specifically to limit 32-bit mode. Since that would mean adding
transistors though, and special-casing, it was indeed not very logical
to be afraid of such. :) Thanks again!
 
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