PC100 SDRAM

I Have a Celeron running at 450 Windows 98, normal ancilliaries, working perfectly except, 64M memory, 3.3V unbuffered normal stuff. But I wanted to add a further 128m so Bought the genuine article from compaq, 3.3V unbuffered SDRAMM etc looks the same!, tried it in all 3 slots on the ASUS motherboard.  PC could not see it. tried all combinations, and only the 64M could be seen not 196M. Took out the 64M and left the 128M in and now I have 128M fully functional.  Can they not be mixed? do I swap the 64 M for another 128M or will it not see that also.
johnnynAsked:
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micro66Connect With a Mentor Commented:
I think one is ECC (72) and the other is just EDO (64).  Don't think they'll work together for that reason.
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hewittgCommented:
John,
If I remember correctly, they cannot be mixed.  You will have to do the swap thing.  Others will chime in to verify.

Glenn
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SuperKirkerCommented:
Maybe you need to change a jumper or BIOS setting to enable more slots on the mobo?

And is the existing memory PC100?
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magarityCommented:
Most strangeness!  There's no reason why you can't mix sizes as long as the ram is all the same voltage/speed/unbuffered, etc, etc.

I have a 128 and a 16 in mine and they both work fine together.

Have you asked (emailed) compaq about this?
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sorgieCommented:
I assume your MB supports more then 128??
Also I assume your Bios self recognizes
Your memory?
I don't believe the sticks have too be the same amt of Megs too work?
Do you have your MB doc's usually they tell you how too configure different memory sizes. Some MB like the smaller in the first bank and some the opposite.
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blueforceCommented:
100MHZ and 66MHZ aren't compatible.  The system bus can support RAM at one speed or the other not both.
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viper5by5Commented:


As sorgie said, the mem dosen't have to be the same amt of megs too work. But ask blueforce said they still have to be the same type to work. the systems bus can't run at two different speeds at the same time, only one.

i would stick the 128mb in there alone, and try and save up so that you can trade in your 64mb stick for another 128mb stick which is the same as the one you just brought.

 
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oldgreyguyCommented:
what model is the ASUS mainboard
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EMTECHCommented:
make sure that both models are PC100. You may have been sold ordinary sdram (for standard pentiums). If that is not right then contact your motherboard supplier and see maybe the board is faulty.

Good Luck
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SuperKirkerCommented:
How about this?  One may be CAS2 and one may be CAS3!!!

The older RAM is obviously good at 100MHz bus that the PC100 is good at...the only way to get a Celeron to run at 450 (I assume you're using the venerable 300a - using the same thing here) is to use a 100MHz bus.  My best guess is that the newer stuff you got is CAS2 and the older stuff is CAS3.  Don't ask me what the difference is, I've just heard that CAS2 is faster, but I wouldn't be surprised to see that they won't work together.
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johnnynAuthor Commented:
Adjusted points from 50 to 80
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johnnynAuthor Commented:
Thanks all for your replies. Can anyone confirm if
the following explanation fits:-

Facts:-
PC is 1 year old
Both 64 and 128 sticks are 100MHz PC100 3.3V Unbuf.
Both work independantly but not together
Motherboard is ASUS P2B AGP 440BX Pentium/Celeron 2
I'm running a Celeron 300 Clock to 450
Bus Freq 450Mhz  External clock 300Mhz
No Bios settings to my knowledge to be changed except
Data Integrity Mode works both at ECC and Non ECC
with 128 stick
But 128 stick has 9 chips and is marked as follows
MT18LSDT1672G-10CB1  PC100 322-620R  9944AAMM66.022
Chips say 4BlC16M4A2
the 64 stick has 8 chips and no labels visible
Chips say GM72V66841ET7J

Is it that one is 64 bits wide the other 72 bits
(9 chips) hence they Data Integrity Mode cannot cope
with both?

If so, anyone want to buy a 64M 64 bit wide Mem stick?
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oldgreyguyCommented:
Your MT (Micron) module is 72bits wide, not real sure on the other, but it is most likely 64 bits wide.

It would be my guess that the "unknown" module is the culprit as far as compatibility.

I would head back to the place you purchased the 128mb module and see if they will trade you something for the 64mb module

bill
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johnnynAuthor Commented:
Thanks for all the help

Exchange on its way!

john
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johnnynAuthor Commented:
Can't I give two people points for similar but helpful answers?

john
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hewittgCommented:
Go to community support and make your request there.
Glad you got your question answered.

Glenn
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