Not all combination of memory that should work will work, and mixing brands
and speeds is rarely a good idea.

Try removing all memory and installed only the newest chips and see what
that does.

Also, are you sure that your PC can handle all that memory.  Just because it
fits does mean it will work.  Some motherboards have limitations less than
the total that can be physically inserted.

Did you check with a reputable memory supplier for exactly what memory your make and model would
use?
Try www.crucial.com for a check.
A quick look showed a whole lot of models of the IBM PC300PL series.
Each took a different type of RAM chip.
Most of which were PC133's.

Some chipsets will only cache a certain amount of system RAM. For
example, my SiS5597/5598 chipset will only cache up to 128MB. This
means that if I add more memory the system will slow down. However, I
could still see a benefit if I have a memory hungry app which would
otherwise rely on virtual memory, ie an app that swaps to disc.

I doubt that this would explain your "seize ups", though.

- Franc Zabkar

I specifically remember an issue with some motherboards
which would not work when all three memory banks were populated.

It may have been Rambus boards, though, so that may not be relative here.

However, this might....

http://episteme.arstechnica.com/eve/ubb.x?a=tpc&s=50009562&f=77909774&m=501000044631

Specifically,

"Mixing RAM
Another area fraught with myth and legend.
"Mix different modules", they say, "and the spirits of fractional
recognition shall haunt thee!"
In reality, it's more likely to be a case of density problems, as seen
above.
The user has 64MB in his BX based P2, adds 256MB, only sees 192MB
because his 256MB stick contains 32Mx4 DRAMS,
which BX can only address as 16Mx4, thus is only seen as 128MB.

The other mixing problem can be timings, which is either PEBCAK or a BIOS
bug.
Usually the former. User has his PC2700 set to 2-6-2-2,
adds more PC2700 which is only specified for CL2.5,
and forgets to update his RAM timings.

The result is an overclocked DIMM which may or may not work.
If in doubt, put BIOS settings on "Auto" for everything RAM related
- BIOS will then ask the RAM how fast it can go.

Finally, mixing different densities (getting them in the wrong order)
can cause problems. The lowest density should be nearest
to the chipset, since it is likely to have the most DRAMs on it,
and thus be a heavier load on the bus.

This can cause problems associated with either of the two mixing
problems above, so eliminate those
(i.e. VIA chipsets have no problem with density,
and you can check your timings) before assuming this.

Swapping slots usually solves a problem caused by this."

(1) Still, here are other RAM testers...
http://www.simmtester.com/PAGE/products/doc/docinfo.asp RAM tester
http://www.memtest86.com/ RAM tester
http://oca.microsoft.com/en/windiag.asp RAM tester

But are you sure it isn't something else causing the pauses?

(2) Do you have an exotic RAM setting?

    (a) Is anything checked at...
         "START button, Run, MSConfig, Advanced button",
         other than Enable Startup Menu?

    (b) Is there anything in...
         "MSConfig, System.ini tab, [vcache] section"?

    (c) In the [386enh] section, is there a "MaxPhysPage" entry?

    (d) Is Windows properly managing the Swap File?
         It manages it based on what is shown shadowed in min & max
         at "R-Clk My Computer, Properties, Performance tab, Virtual
         Memory button". That is OK at defaults of zero & "No maximum".

(3) I know I can get that symptom at times by turning on McAfee's
auto-System Scan. Maybe try the clean boot procedure in Terhune's
signature, or...

"START button, Run, MSConfig" & turn off the Startup Group, Config.sys &
Autoexec.bat. (Note: when you later turn them back on, all items in them
will get checked. So, note what may be unchecked first.)

Do you get the delays now? If not, there is some troubleshooting to
do, using MSConfig...

http://support.microsoft.com/default.aspx?scid=kb;en-us;281965
How to Troubleshoot Using the Msconfig Utility with Windows 98
(281965) - This article describes how to use the Microsoft System
Configuration (Msconfig) utility to troubleshoot configuration errors in
Windows 98 and Windows 98 Second Edition.

BUT BE CAREFUL-- better not disable System.ini & Win.ini, because that
can be trouble. Well, if you are sure of your Registry backups, actually
those two can be recovered this way...

(a) Boot to DOS. (Hold Ctrl for the Startup Menu, & select "Command
Prompt Only".)
(b) Scanreg  /Restore
(c) Ctrl-Alt Del to Windows.

It will offer five dates. Choose the one of the last successful boot, to
start. These backups are done at boot, not at shut down. This should be
safe to do, if you haven't done anything to files in the mean time. This
will not restore files other than those .ini's & the Registry. It only
restores settings.

I would like to thank Bob Harris, Richard in AZ, Gary S, Terhune, Franc
Zabkar, Hugh Candlin, and PCR for their replies.  I would have replied
sooner, but life kept intruding the more important things, like computing.

It took me awhile to work through all the websites, tests, and suggestions
that I was given.  The answer to my problem was two fold.  The first step
came from another thread talking about "hopping cursors."  I went to
Msconfig and eliminated some startup programs.  This brought the seizing
down to a bearable level.  However, the real fix came when I removed the old
stick of memory.

Going back to Sandra Lite I noticed that the new memory was error
correcting, but the old memory did not seem to be.  I pulled the old stick,
and lo-and-behold, the improvement in performance was achieved!

I really appreciate the help offered to me and others in this forum.  The
wealth of knowledge here has greatly advanced my computer skills/knowledge.

Thanks,
Dan Hacker