Guidance sought on how memory is used


K

km

My situation - I regularly collect older PCs to pass on to disabled
members of a Charity. Consequently I have a large number of small
SDRAM modules (mainly 32mb & 64mb). Occasionally I get 128mb and very
rarely 256mb.

I have a 256mb piece of memory that I put on one side some time ago as
I believed it was faulty because errors occurred when trying to
install WinXP (I probably ran MemTest 86 at the time). During the last
few days I set up a system with 128mb to run WinXP and this is working
OK for basic Word Processing. I decided to give the 256mb chip a try
and added that to the existing chip with a noticeable benefit and no
errors so far.

My Question - (I accept that the improvement shown means the new chip
has been accessed) How is the memory utilised by the system? Does
the Operating system apportion work to each module so that they are
all partially in use or is each module fully used before the system
moves on to make use of the next module.

I would like guidance, not only for my own information but to ensure
that the recipient of the Computer does not have errors cropping up at
a later date when additional software is installed which causes all of
the 256mb chip to come into use.


Hope this makes sense.

km

Also posted in uk.comp.homebuilt
 
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R

Rod Speed

km said:
My situation - I regularly collect older PCs to
pass on to disabled members of a Charity.

Why cant those buy PCs like anyone else ?
Consequently I have a large number of small SDRAM modules
(mainly 32mb & 64mb). Occasionally I get 128mb and very rarely 256mb.
I have a 256mb piece of memory that I put on one side some time
ago as I believed it was faulty because errors occurred when trying
to install WinXP (I probably ran MemTest 86 at the time).

Its much more likely that the bios in that system didnt use it properly.

Most socket 7 systems didnt even bother to read the spd on the dimm and
use the timing detail specified in there, they just tried to guess that stuff.
During the last few days I set up a system with 128mb to run
WinXP and this is working OK for basic Word Processing. I
decided to give the 256mb chip a try and added that to the
existing chip with a noticeable benefit and no errors so far.

Which just means that this system has read the
spd and is using the data in it or is guessing better.
My Question - (I accept that the improvement shown means the new
chip has been accessed) How is the memory utilised by the system?
Does the Operating system apportion work to each module so that
they are all partially in use or is each module fully used before the
system moves on to make use of the next module.

Its much more complicated than that with a modern OS like XP.
It assumes that all the ram is good and with that much physical ram
uses all of it at boot time to give the best perception of performance.
I would like guidance, not only for my own information but
to ensure that the recipient of the Computer does not have
errors cropping up at a later date when additional software is
installed which causes all of the 256mb chip to come into use.

That wont happen with that amount of physical ram, it will all be used right now.

If you want more confidence that the correct timing detail is being used, run
the Prime95 test very agressively and do an overnight run of memtest86.
Hope this makes sense.

Yes it does.
 
P

Paul

km said:
My situation - I regularly collect older PCs to pass on to disabled
members of a Charity. Consequently I have a large number of small
SDRAM modules (mainly 32mb & 64mb). Occasionally I get 128mb and very
rarely 256mb.

I have a 256mb piece of memory that I put on one side some time ago as
I believed it was faulty because errors occurred when trying to
install WinXP (I probably ran MemTest 86 at the time). During the last
few days I set up a system with 128mb to run WinXP and this is working
OK for basic Word Processing. I decided to give the 256mb chip a try
and added that to the existing chip with a noticeable benefit and no
errors so far.

My Question - (I accept that the improvement shown means the new chip
has been accessed) How is the memory utilised by the system? Does
the Operating system apportion work to each module so that they are
all partially in use or is each module fully used before the system
moves on to make use of the next module.

I would like guidance, not only for my own information but to ensure
that the recipient of the Computer does not have errors cropping up at
a later date when additional software is installed which causes all of
the 256mb chip to come into use.


Hope this makes sense.

km

Also posted in uk.comp.homebuilt

As Rod mentioned, Prime95 from mersenne.org is a good test for a computer.
It is a program that searches for prime numbers. The program has a
testing mode, called the Torture Test. Basically, it will grab a good
sized chunk of system memory, and compute things like FFTs (fast
fourier transforms) and the program knows what the answer should be.
If the memory or the CPU is defective, the results will show up in
a few minutes, as a "rounding error". If any errors show up, then
you know that the CPU or memory part of the system are not stable.
If the program runs for hours and doesn't detect any errors, then
you know that the chunk of memory it tested is in good shape.

Since running Prime95 keeps the CPU at the 100% level while it
is running, you also get a chance to verify that the cooling
system in the computer is working properly. On modern motherboards,
there will be a monitoring chip on the motherboard, and you can
read out the temperature with that, and a program like Speedfan or
MBM5. Checking the heat level at 100% loading is valid, because
when your computer build is in the hands of a customer, they
won't know or care whether the CPU is at 0% or 100%. So 100%
testing while the computer is in your hands, helps ensure there
are no surprises when the computer is in the hands of someone who
doesn't care about temperatures and such things.

Paul
 
K

km

Why cant those buy PCs like anyone else ?

Because they are people with Multiple Sclerosis who attend a Day
Centre. In the main MS affects women when they turn 50. Often the
husbands cannot cope and they wife is left on her own. A change like
that often means no income and a dependancy on the Day Centre for
reduced cost meals, hairdressing, physiotherapy etc They are more
often and not forced to move downmarket as far as housing is
concerned. This paints a picture of the person I am trying to help.
Their use of PCs may well be playing simple games or letter writing.
Hands are often adversely affected by MS so ideally Voice Controlled
PCs would be best but would be beyond the capability of the low end
systems I have put together so far. Donated PCs often do not work or
have been stripped of Hard Drives and Memory (of any larger size -
that is why I get an abundance of 32mb chips) The OS is Win 98 in the
main but am trying to put in WinXP if possible.
Its much more likely that the bios in that system didnt use it properly.

The 256mb chip was used more than once with different motherboards and
resulted in problems transferring the files to install WinXP. I also
ran Memtest86 which indicated problems. I can't remember exact info as
it was a year or two back. Will run tests again.
Most socket 7 systems didnt even bother to read the spd on the dimm and
use the timing detail specified in there, they just tried to guess that stuff.

This gives me more hope (?) if I read you correctly a more recent BIOS
may be using the memory in a different way than older boards?
Which just means that this system has read the
spd and is using the data in it or is guessing better.

I keep my fingers crossed that this is the case. I guess the wisest
thing is to load more software that is memory hungry and see if it
copes.
Its much more complicated than that with a modern OS like XP.
It assumes that all the ram is good and with that much physical ram
uses all of it at boot time to give the best perception of performance.

I wondered if my question was naive - at the back of my mind I
realised that the system would use all of the memory available so that
it would run tasks more quickly (not sure if thats the right way to
describe it) but a thought also crossed my mind that if the tasks
being performed were low memory based then the faulty elements of the
memory had not yet been actioned. That is my area of ignorance and why
I posed the question.
That wont happen with that amount of physical ram, it will all be used right now.

If you want more confidence that the correct timing detail is being used, run
the Prime95 test very agressively and do an overnight run of memtest86.
Will do that. Although I am still interested in learning from replies
as I am likely to come across similar situations when using larger
memory modules. I can pick and choose with 32mb and 64mb but when
256mb come my way I think it will be because the previous owner wasn't
confident in their quality. Hopefully by having a better understanding
I will know whether these chips can be of any use at all. Again my
naive thinking was that I could put in a couple of smaller modules to
set up WinXP and then bolster the system by adding a potentially weak
larger module which would not need to be used to run the OS but would
be available if larger more demanding programmes were run.
Yes it does.
Thank you for your response.

KM
 
R

Roy Coorne

....

Why can't you obey the rules of P(olitical) C(orrectness) like anybody
else?!

Roy
 
O

OSbandito

Just a side comment. If you have a lot of spare boards around, store
them in either conductive bags or simply aluminum foil. I'm sure you
already use a grounding strap when installing boards. Static sparks,
usually not visible, can generate over 50kv and punch holes in your
memory, resulting in small but annoying errors.
 
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R

Rod Speed

Because they are people with Multiple Sclerosis who attend
a Day Centre. In the main MS affects women when they turn
50. Often the husbands cannot cope and they wife is left on
her own. A change like that often means no income

Surely your govt provides an income for those ?
and a dependancy on the Day Centre for reduced cost meals,
hairdressing, physiotherapy etc They are more often and not
forced to move downmarket as far as housing is concerned.
This paints a picture of the person I am trying to help.
Their use of PCs may well be playing simple games or letter
writing. Hands are often adversely affected by MS so ideally
Voice Controlled PCs would be best but would be beyond the
capability of the low end systems I have put together so far.

Yeah, thats another reason to just buy a decent modern PC.
Donated PCs often do not work or have been stripped of
Hard Drives and Memory (of any larger size - that is why
I get an abundance of 32mb chips) The OS is Win 98 in
the main but am trying to put in WinXP if possible.

I cant help feeling it makes more sense to use decent modern
PCs instead, by spending less on something else if necessary.

Certainly with assistence to get it working for them tho.
The 256mb chip was used more than once with different motherboards
and resulted in problems transferring the files to install WinXP.

Thats not unusual with socket 7 systems that try to guess the ram
specs instead of reading the spd. With some ram modules they
mostly get it wrong because the specs are different to what they
assume they will be, particulary with the later higher density modules.

Ram has always been a problem with socket 7 systems for that reason.
I also ran Memtest86 which indicated problems.

Yes, but again, all that shows is that the bios isnt using the appropriate timing detail.
I can't remember exact info as it was a year or two back. Will run tests again.

Not much point, all it confirms is that the wrong timing detail is being used.
This gives me more hope (?) if I read you correctly a more recent
BIOS may be using the memory in a different way than older boards?

Later systems do read the spd on the memory modules and
are supposed to use the appropriate timing detail from the spd.

They dont always do it successfully tho, we are currently seeing
a rash of problems with DDR2 ram where the bios still cant get it
right and wont even boot, lot alone use timing detail that ensures
that you dont ever get any memory errors.
I keep my fingers crossed that this is the case. I guess the wisest thing
is to load more software that is memory hungry and see if it copes.
I wondered if my question was naive - at the back of my mind
I realised that the system would use all of the memory available
so that it would run tasks more quickly (not sure if thats the right
way to describe it) but a thought also crossed my mind that if the
tasks being performed were low memory based then the faulty
elements of the memory had not yet been actioned. That is my
area of ignorance and why I posed the question.

And sometimes you just need to discuss it to realise the brain fart too.
Will do that. Although I am still interested in learning from replies
as I am likely to come across similar situations when using larger
memory modules. I can pick and choose with 32mb and 64mb
but when 256mb come my way I think it will be because the
previous owner wasn't confident in their quality.

Not necessarily, they are being discarded now as people are finding
ram is cheap enough to make 1G and 2G totals trivially affordable
and many packaged systems only came with 256M standard.
Most systems dont allow all that many total ram modules, so
you do need to discard 256M modules if you want 1G or 2G total.
Hopefully by having a better understanding I will
know whether these chips can be of any use at all.

Ram isnt supplied flakey, and hardly ever goes flakey over time.
When memory errors are seen, its normally a timing problem.
Again my naive thinking was that I could put in a couple of smaller modules
to set up WinXP and then bolster the system by adding a potentially weak
larger module which would not need to be used to run the OS but would
be available if larger more demanding programmes were run.
Thank you for your response.

No problem, happy to discuss it for as long as you need.
 
K

km

Surely your govt provides an income for those ?
This means income from earnings. They receive benefits which are for
basic living costs.

My approach to voluntary activity is that I try and help whoever I
can. I would not attempt to do any means testing or make judgements
about who should receive help and who shouldn't.
Yeah, thats another reason to just buy a decent modern PC.

There are no costs involved I make use of purely donated items. That
goes from hardware to Operating Systems (licences for all Windows OS,
95 through to XP, have been given in).

I cant help feeling it makes more sense to use decent modern
PCs instead, by spending less on something else if necessary.
See my comments above - there is no expenditure. Other than my own
time and travel costs plus the occasional minor item.

Ram has always been a problem with socket 7 systems for that reason.

You mention Socket 7 motherboards in particular but I have a range of
boards, moving more recently to Socket 478 for Pentium 4. If Memtest86
is used with the 256mb module inserted on that board, I assume, from
what you say, that it is more likely that any errors reported would be
genuine, as opposed to the BIOS not using the appropriate timing
detail.


Thanks again

km
 
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R

Rod Speed

This means income from earnings.

Nope, benefits are also income.
They receive benefits which are for basic living costs.

The reality is that they pay for more than that in every modern first world country.

I know a few who have different medical problems that
live quite well on their benefits and dont need donated
PCs, they can buy new PCs fine, and have done that.
My approach to voluntary activity is that I try and help whoever
I can. I would not attempt to do any means testing or make
judgements about who should receive help and who shouldn't.

Sure, but thats an entirely separate matter to what makes sense PC wise.
There are no costs involved I make use of purely donated items.
That goes from hardware to Operating Systems (licences for all
Windows OS, 95 through to XP, have been given in).

Sure, but you can end up with a much more capable PC if you just buy one.
See my comments above - there is no expenditure. Other than
my own time and travel costs plus the occasional minor item.

Doesnt mean its the most viable approach with someone who is
significantly disabled and who will benefit from a voice activated system.
You mention Socket 7 motherboards in particular but I have a range
of boards, moving more recently to Socket 478 for Pentium 4.

OK, those are much less of a problem memory wise.
If Memtest86 is used with the 256mb module inserted on that
board, I assume, from what you say, that it is more likely that
any errors reported would be genuine, as opposed to the
BIOS not using the appropriate timing detail.

Nope, its very rare to see a real failure of a memory module that
hasnt been aggressively abused. Problems seen with memtest86
are almost always just the wrong timing or voltage used.

You still see that even with the latest Core 2 Duo systems
which wont even boot with particular memory installed.
Thanks again

You're welcome.
 

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