RAM detection problems on P2B series boards

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P2B

Anyone know what causes erratic RAM detection on P2B series
motherboards, particularly at 133Mhz FSB?

I've never had any problems running 768MB (3x256MB) on my P2B-DS boards,
and one is fully loaded with a gig.

I recently purchased a bunch of used 256MB sticks, mostly Micron but a
few are other brands, with the intent of upgrading our single processor
P2B systems from 256 to 512 or 768MB.

I tested it all in matched pairs on a modified P2B-AE running a P3-S
1.4Ghz CPU (133Mhz FSB) - configured the BIOS for 222 timings regardless
of SPD, and ran memtest86 3.0 in all tests mode for at least 5 full
passes on each pair.

All testing completed without a single problem or error, but when I
install in the target systems I encounter nothing but grief :-(

On one P2B-AE system, the BIOS only detects either 64MB or 128MB from
cold start when 512MB is installed, and it won't POST on reset - has to
be powered off to try again. I tried all the tested pairs, and also
mixed brands, but couldn't get it to detect more than 128MB when both
RAM slots were filled - not even at 100Mhz FSB and 333 timings - but
this one has the same board revision and BIOS as the test system that
detected 512MB every time!

Similar story on a P2B-S machine, although I eventually found a
mixed-brand pair that works properly in this system - but no way will it
detect three sticks.

RAM voltage on all systems is within 100mV of 3.4V, the only significant
difference is Tualeron processors in the target systems vs. a P3-S in
the test system - but that seems unlikely to affect RAM detection.

All very mysterious and annoying - comments or suggestions appreciated.

P2B
 
P2B said:
Anyone know what causes erratic RAM detection on P2B series
motherboards, particularly at 133Mhz FSB?

I've never had any problems running 768MB (3x256MB) on my P2B-DS boards,
and one is fully loaded with a gig.

I recently purchased a bunch of used 256MB sticks, mostly Micron but a
few are other brands, with the intent of upgrading our single processor
P2B systems from 256 to 512 or 768MB.

I tested it all in matched pairs on a modified P2B-AE running a P3-S
1.4Ghz CPU (133Mhz FSB) - configured the BIOS for 222 timings regardless
of SPD, and ran memtest86 3.0 in all tests mode for at least 5 full
passes on each pair.

All testing completed without a single problem or error, but when I
install in the target systems I encounter nothing but grief :-(

On one P2B-AE system, the BIOS only detects either 64MB or 128MB from
cold start when 512MB is installed, and it won't POST on reset - has to
be powered off to try again. I tried all the tested pairs, and also
mixed brands, but couldn't get it to detect more than 128MB when both
RAM slots were filled - not even at 100Mhz FSB and 333 timings - but
this one has the same board revision and BIOS as the test system that
detected 512MB every time!

Similar story on a P2B-S machine, although I eventually found a
mixed-brand pair that works properly in this system - but no way will it
detect three sticks.

RAM voltage on all systems is within 100mV of 3.4V, the only significant
difference is Tualeron processors in the target systems vs. a P3-S in
the test system - but that seems unlikely to affect RAM detection.

All very mysterious and annoying - comments or suggestions appreciated.
Click to expand...

Assuming your modules are correct (low-density, organized
into two logical banks of 128MB per dimm instead of one
256MB bank), the problem is likely related to voltage. Most
BX board designs, even those with three dimm slots instead
of four, have anemic 3.3v power supplies to these slots.
Many share power between slots, so e.g. you might get one
running with slots 1 and 3 populated but not 1 and 2. Or
with 1 and 2 populated, but not all three. Etc.

Not much you can do other than trial and error.
 
Anyone know what causes erratic RAM detection on P2B series
motherboards, particularly at 133Mhz FSB?

I've never had any problems running 768MB (3x256MB) on my P2B-DS boards,
and one is fully loaded with a gig.

I recently purchased a bunch of used 256MB sticks, mostly Micron but a
few are other brands, with the intent of upgrading our single processor
P2B systems from 256 to 512 or 768MB.

I tested it all in matched pairs on a modified P2B-AE running a P3-S
1.4Ghz CPU (133Mhz FSB) - configured the BIOS for 222 timings regardless
of SPD, and ran memtest86 3.0 in all tests mode for at least 5 full
passes on each pair.

All testing completed without a single problem or error, but when I
install in the target systems I encounter nothing but grief :-(

On one P2B-AE system, the BIOS only detects either 64MB or 128MB from
cold start when 512MB is installed, and it won't POST on reset - has to
be powered off to try again. I tried all the tested pairs, and also
mixed brands, but couldn't get it to detect more than 128MB when both
RAM slots were filled - not even at 100Mhz FSB and 333 timings - but
this one has the same board revision and BIOS as the test system that
detected 512MB every time!

Similar story on a P2B-S machine, although I eventually found a
mixed-brand pair that works properly in this system - but no way will it
detect three sticks.

RAM voltage on all systems is within 100mV of 3.4V, the only significant
difference is Tualeron processors in the target systems vs. a P3-S in
the test system - but that seems unlikely to affect RAM detection.
Click to expand...

My P3B-F runs perfectly with 3x256MB PC133 modules from Crucial
at 100MHz FSB, but at 133MHz FSB (the CPU is a 1.26GHz Tualatin P3)
there are intermittent read errors detected both by memtest86 and
by running heavy application loads. 2x256MB works reliably at 133MHz,
but unfortunately I need all the memory I can get.

I guess I should have bought registered modules :-(

/Mikael
 
BigJim said:
no really the p2b needs low density ram
Click to expand...
You don´t know the i440BX.


Well P2B, I would suggest you

http://free-pu.htnet.hr/BXRAM/

and http://p196.ezboard.com/bcubx
this is a CuBX Forum but very interesting for P2B/P3B users, too.


Don´t forget to use very well RAM for the BX. 133MHz Cl.2 RAM do not have to
work in a BX with 133 2-2-2 setting, but in most cases it does.
You will also find in the Internet some comments about the stability on P2B
derivates and CuBX. So far as I understood, the CuBX and the P3B-F are the
best for overclocking, operating at 150MHz without problems. My P2B-F for
example is finishing at <140MHz, even you can clock it up to 150. But I have
never gone beyond 105MHz, and staying now at 100MHz. For what should I need
more MHz????

Maybe your P2B cannot operate the Tualatin? Voltage regulator?




Best Regards,

Daniel Mandic


P.S.: For BX enthusiasts like me: I have found an article (Japan) about a BX
with <200MHz FSB givin 2100 MHz Tualatin. You would need a Intel extreme
edition to outdistance such a system :-)
I am sure the formerly BX-Designers could make such FSB work
(without overclocking),some years after the official BX-Release, which was
1996.
 
Daniel said:
You don´t know the i440BX.


Well P2B, I would suggest you

http://free-pu.htnet.hr/BXRAM/

and http://p196.ezboard.com/bcubx
this is a CuBX Forum but very interesting for P2B/P3B users, too.


Don´t forget to use very well RAM for the BX. 133MHz Cl.2 RAM do not have to
work in a BX with 133 2-2-2 setting, but in most cases it does.
Click to expand...

IME Micron PC133 CL3 always tests clean and runs stable at 222 on P2B
boards. Other brands frequently show a few errors per pass in memtest86
and must be run at 333 for stability.
You will also find in the Internet some comments about the stability on P2B
derivates and CuBX. So far as I understood, the CuBX and the P3B-F are the
best for overclocking, operating at 150MHz without problems. My P2B-F for
example is finishing at <140MHz, even you can clock it up to 150. But I have
never gone beyond 105MHz, and staying now at 100MHz. For what should I need
more MHz????
Click to expand...

I have two P2B-S systems running Tualatin processors @ 150Mhz FSB with
512MB (2x256) of Corsair PC150 CL2, long term stable. I'd get more of
the same RAM if I could find it...
Maybe your P2B cannot operate the Tualatin? Voltage regulator?
Click to expand...

The systems have all been running Tualatins @ 133Mhz FSB with 256MB for
1-2 years.

What I don't understand is why they won't detect 512MB - but my test
system with the same board and BIOS revisions, and same RAM voltage
(within 100mV) does so every time.
Best Regards,

Daniel Mandic


P.S.: For BX enthusiasts like me: I have found an article (Japan) about a BX
with <200MHz FSB givin 2100 MHz Tualatin. You would need a Intel extreme
edition to outdistance such a system :-)
Click to expand...

I find that hard to believe - even the best Tualatin cores top out
around 1700Mhz, and what would you use for RAM?

P2B
 
P2B said:
IME Micron PC133 CL3 always tests clean and runs stable at 222 on P2B
boards. Other brands frequently show a few errors per pass in memtest86
and must be run at 333 for stability.
Click to expand...

Lucky one..
I have two P2B-S systems running Tualatin processors @ 150Mhz FSB with
512MB (2x256) of Corsair PC150 CL2, long term stable. I'd get more of the
same RAM if I could find it...
Click to expand...

Very expensive...
What I don't understand is why they won't detect 512MB - but my test
system with the same board and BIOS revisions, and same RAM voltage
(within 100mV) does so every time.
Click to expand...

The BX cannot fully recognise 512MB Dimms. If you mean 2x256MB then try to
insert one in slot0 and the other in slot2, leaving the second slot, slot1
empty.
I find that hard to believe - even the best Tualatin cores top out around
1700Mhz, and what would you use for RAM?
Click to expand...

Who knows what kind of RAM you can buy in Japan. As you know, the most
companies, like NEC are from Japan. Maybe a PC180 Cl.2!? With special
cooling you can go to unbelievable MHz. But this is all uninteresting. A
fine PC should have a consumption of 50 to maximal 200 Watts. With more I
should sit on it and drive and not siiting behind it ;-)




Best Regards,

Daniel Mandic
 
btw, you'd rather should read
http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html which is the
original source. I don't like others to copy whole pages 1:1 instead of
linking but don't care enough to really do something about it...
I find that hard to believe - even the best Tualatin cores top out
around 1700Mhz, and what would you use for RAM?
Click to expand...
Those are probably the same guys which overclock P4 to over 5Ghz and
other similar crazy things. Liquid nitrogen will help a lot to make that
1700Mhz-limited tualatin run faster :-)

Roland
 
btw, you'd rather should read
http://homepage.hispeed.ch/rscheidegger/ram_bx_faq.html which is the
original source. I don't like others to copy whole pages 1:1 instead of
linking but don't care enough to really do something about it...
Click to expand...

Hi Roland, nice to see you here.


I have your link in my Favorites, too. The homepage of the other link
contains really a copy of yours. But the guy was so kind to leave your name,
at least.


High density. I did not know that the 32Mx4 architecture was called so. But
when you count the RAM blocks in a 16Mx8 it would be more likely a high
density. 8 is more than 4 ;-)



Best Regards,

Daniel Mandic
 
P2B said:
Anyone know what causes erratic RAM detection on P2B series
motherboards, particularly at 133Mhz FSB?

I've never had any problems running 768MB (3x256MB) on my P2B-DS boards,
and one is fully loaded with a gig.

I recently purchased a bunch of used 256MB sticks, mostly Micron but a
few are other brands, with the intent of upgrading our single processor
P2B systems from 256 to 512 or 768MB.

I tested it all in matched pairs on a modified P2B-AE running a P3-S
1.4Ghz CPU (133Mhz FSB) - configured the BIOS for 222 timings regardless
of SPD, and ran memtest86 3.0 in all tests mode for at least 5 full
passes on each pair.

All testing completed without a single problem or error, but when I
install in the target systems I encounter nothing but grief :-(

On one P2B-AE system, the BIOS only detects either 64MB or 128MB from
cold start when 512MB is installed, and it won't POST on reset - has to
be powered off to try again. I tried all the tested pairs, and also
mixed brands, but couldn't get it to detect more than 128MB when both
RAM slots were filled - not even at 100Mhz FSB and 333 timings - but
this one has the same board revision and BIOS as the test system that
detected 512MB every time!

Similar story on a P2B-S machine, although I eventually found a
mixed-brand pair that works properly in this system - but no way will it
detect three sticks.

RAM voltage on all systems is within 100mV of 3.4V, the only significant
difference is Tualeron processors in the target systems vs. a P3-S in
the test system - but that seems unlikely to affect RAM detection.

All very mysterious and annoying - comments or suggestions appreciated.

P2B
Click to expand...

Update - the problem appears to be BIOS/CMOS related.

After much trial and error, I have determined the following RAM upgrade
procedure yields successful results when upgrading P2B series boards
running at 133Mhz FSB or higher from 1 x 256MB to 2 or 3 x 256MB:

1. Clear CMOS
2. Set FSB to 100Mhz
3. Install desired RAM configuration
4. Power on, wait for ESCD and DMI update message display
5. Press reset, enter BIOS and restore previous settings, save & exit
6. Wait for ESCD and DMI update message display
7. Power off, restore previous FSB setting
8. Power on, system should detect all RAM and boot normally

Notes:

- Doesn't appear to make any difference which RAM slots are populated
- Steps 2 & 7 may not be required on some boards, but initial detection
of new RAM appears to be more reliable at 100Mhz FSB
- Step 4 may not be required on some boards, but allowing BIOS to update
DMI/ESCD with values from SPD prior to manually setting RAM timings
appears to be more reliable

Clearing CMOS is the key step - a couple of my systems wouldn't even
POST after I powered down and added another stick of RAM, but worked
fine after clearing CMOS.

P2B
 
I have the PB3-F, fully loaded pci and 3x256mb dimms (DS)(cl222). I
did not notice this same problem until I swapped cpu's to a 133mhz
coppermine from a 100 mhz coppermine. Now the ram registers as cas333
10 instead of 222 8. Setting this manually is no problem and the
system runs fine. But there is an intermintant problem where the
memory may or may not be all counted "AFTER" a cmos change and save.
It's wierd and I will be testing the dimms individually, even though
I'm sure it is something else, possibly something along the lines of
what you have described...
FYI
 
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