Re: How much RAM?

[Matt Ion <soundy -at- NEXTLEVEL -dot- COM>]

On Sat, 18 Nov 1995 10:51:42 -0500 you wrote:

>I upgraded from 8MB to 16MB about a 6 months ago.  I'm seriously considering
>adding another 16MB.

>I run Win95 with the MS Office suite, CorelDraw3, Micrografx GraphicsWorks
>(including their photo touchup package), PaintShopPro, and PagePlus2 for the
>little bit of true DTP I do.

One of the more common causes of General Protection Faults in Windows 3.x is
lack of memory - loading a large file fills up the RAM and the file can
potentially overwrite vital system code in memory.  Increasing the swapfile
size can help matters, but isn't a cure for the real problem (poor memory
handling).  More RAM generally makes a big difference.

In addition to the amounts of raw memory necessary for handling large files
(documents/graphics), more memory can have a profound effect on overall
performance.

OS/2, for example, can provide virtual memory up to the limits of the
freespace on the hard drive by using a dymamic swapfile, and because it's a
protected mode system, applications are simply not allowed to overwrite system
code in memory.

Applications are then simply informed by the operating system that they have
all the memory they require available to them, and they run happily along, not
knowing or caring whether that memory consists or real RAM, or drive-based
virtual RAM.

Of course, a hard drive is some 500 to 1000 times slower than RAM, which means
the more the system has to go to the disk, the slower things get.  I could
load up a 25MB graphic file into, say, CorelDraw! for OS/2, even on an 8MB
machine, and it will WORK... but it'll be slow because most of that 20MB is in
the swapfile.

I can do the same for a Windows app running in OS/2 by simply telling that
session it has available however much memory it needs (up to 32MB EMS, 16MB
XMS, and a full 512MB of DMPI memory resources for each session), with the
same limitation - it will slow down the more it has to go to the hard drive to
provide that memory once it's required (actual memory resources are
pre-allocated, but called upon only on demand).

Now, I can't speak authoritatively for Windows95, but I believe it uses a
similar swapfile scheme now (at least when running within the GUI).  As long
as you're using native 32-bit applications, you're generally safe from GPFs as
well, since they do run in protected mode.  However, watch out loading up any
of your old Win3.x apps, since they can still cause the same problems for the
same reasons.

But again, the same performance issue arises - once the system has to start
swapping to disk, it's going to slow down.  The more RAM you have, the less it
has to swap.

>I also run my client's proprietary process control engineering software;
>that's where I really need the extra RAM.  They recommend 64MB to THEIR
 clients!

Nice.  64MB, forget the swapfile altogether!  :)



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