excerpted from a recent fred langa LangaList Plus!....
Tons Of RAM = Memory Hell?
"Kalle Wesala wanted a PC with a full 1.2 GB (!) of RAM, in the form of
two 512MB memory strips. Trouble is, some versions of Windows can have
trouble with that much RAM:
I've fallen into memory Hell buying the new 512 meg dram
strips. When I expanded my system by 512 meg Norton reported
bad memory at 221 meg even though both 256 meg sticks checked
good by themselves. each 512 meg stick I bought also checked
bad at same place.
Widows started failing and I found help in the knowledge base,
I changed Vcache in system.ini as directed in Q108079, Q109845
and Q253912....
This is a problem that traces its roots all the way back to Windows
3.11, when the thought of a system with 1.2GB of RAM was inconceivable.
In fact, back them, many high-end systems shipped with a total of just 4
or 8 megs of RAM. There are wristwatches with more RAM than that today.<g>
But some of Windows9X-based systems (including WinME) retain some old
limitations: The problem is that there's a finite number of memory
addresses available to the OS for memory management, and a system with
large amounts of RAM may simply run out. Note that this isn't running
out of memory (although that's one way Windows may report it); it's
actually running out of ways to access the memory. It's a Windows
problem, not a hardware problem. (Note that NT/Win2K and XP do not have
this software problem.)
The three KnowledgeBase articles Kalle mentions can help:
"Out of Memory" Error Messages with Large Amounts of RAM Installed:
support.microsoft.com
How Windows 95 Manages the Size of the Disk Cache
support.microsoft.com
32-Bit File Access Maximum Cache Size
support.microsoft.com
But sometimes, it's not Windows: Some system BIOSes and chipsets also
can stumble with large amounts of RAM; and sometimes, RAM chips
themselves are flawed.
Kalle checked for bad RAM by swapping the RAM strips, but got the same
error from both. While this doesn't rule out bad RAM, it would be an odd
coincidence for both strips to fail at exactly the same place. That
leaves a hardware or motherboard or BIOS problem as a possibility.
The Norton test Kalle used runs inside Windows, and so does not "see"
the RAM in a raw form--- it sees what Windows sees.
One simple test is to turn off the system's startup logo screen and set
the BIOS to perform a slow/full boot, including RAM enumeration: At
reboot, you'll see the system hardware--- on its own, before Windows
starts--- briefly count up through however much RAM you have. If this
simple check fails, it suggests the problem is in the hardware: The
system vendor's, BIOS, or motherboard manufacturer's site should be able
to help.
There also are far more comprehensive and complete DOS-based RAM tests
you can use to test the memory subsystem at a low level, outside of
Windows' influence and limitations. For example, see
reality.sgi.com . You can find others with a
web search for RAM TEST.
But note one caveat: When I searched for "RAM test" I found a lot of
information on sheep breeding. Really! 8-)" |
