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need help upgrading ram

by dtsjon / July 3, 2004 5:57 AM PDT

when installing additional memory on my computer, the computer only recognizes half of the new memory. i installed 256 mb of pc133sdrdimm into an hp pavillion 500s computer. the computer had 128 mb sdram in it. the new ram is recognized as 128 mb whether it is installed simultaneously with old ram or alone. i checked bios and it simply shows the new ram as 128 mb regardless of the installation slot.

os: windows xp
model: hp pavillion 500s -- bought november 2001
1.2 ghz intel celeron processor
old ram: 128 mb sdr dimm
new ram 256 mb pc133 sdrdimm -- pny

according to hp website (also pny and crucial), the max ram on this computer is 512 mb.

i need to see if there's anything i am missing/doing wrong ... or just anything i can do to help the upgrade process.

the only thing i can think is that my motherboard simply is maxed out at 256mb

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Re: need help upgrading ram
by armorise / July 3, 2004 6:21 AM PDT

One thing about HPs- they are very picky with the manufacturers that make the memory modules. You stated that no matter what slot the new memory was in- it still registered as 128MB- did it change positions oh the position.. eg:
DIMM 0 - 128MB
DIMM 1 - 0 MB

and then when swapped:

DIMM 0 - 0MB
DIMM 1 - 128MB

or was it identical both times?

Also, you said it stayed the same when installed simeltaneously with the older RAM, do you mean it was still a total of 128MB or was it 256MB (128x2)?
DIMM 0 - 128 MB
DIMM 1 - 128 MB

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Re: need help upgrading ram
by dtsjon / July 3, 2004 7:33 AM PDT

the new memory worked alone in either slot -- when it was in slot 1, the computer read 128 mb in slot 1 ... 0 in slot 2. when it was in slot 2, the computer read 128 mb in slot 2, 0 in slot 1.

when the two were inserted simultaneously, the computer read 128 mb in each slot (256 mb total)

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Intel 810e chipset limitations.
by R. Proffitt Forum moderator / July 3, 2004 7:00 AM PDT

"512 MB maximum using 128 Mbit technology"
- Intel web site.

If we read this and other sites, the memory stick can only have 128 Mbit SDRAM chips. Translated to megabytes, each chip is 16 MegaBytes (MB.)

Your 256 Megabyte memory stick will have at least 16 memory chips on it and may be called DOUBLE SIDED not because the chips are on both sides but that each side of the 128 MB set of chips has its own Chip Select line.

My bet is you have the newer 256 MB memory stick with chips on one side of the stick.


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Re: Intel 810e chipset limitations.
by dtsjon / July 3, 2004 7:39 AM PDT

so is there a solution to how i can get more ram in the computer? do i need to find 256 mb ddr?

or is the 256mb sdr that i am using actually giving the full (practical) 256 mb even though it registers only the 128 mb?

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The solution is simple. Get the right stick.
by R. Proffitt Forum moderator / July 3, 2004 8:23 AM PDT

Because of the limitations of the 810e chipset, sends you another type of memory stick.

And no, what you have is only supplying 128M of ram.


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Re: The solution is simple. Get the right stick.
by dtsjon / July 3, 2004 8:36 AM PDT

ok, so now my ignorance flies to the surface. i thought what i had was the right stick. what specifics do i need to look for ... or will the one that shows up on crucial definitely be the right one.

... the one that shows up on crucial SEEMS to be the same as the one i just purchased.

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Re: The solution is simple. Get the right stick.
by R. Proffitt Forum moderator / July 3, 2004 8:44 AM PDT

I offered the technical reason in as simple words as I could. To recap, the 810e chipset can only address 128 megabytes of RAM with each CHIP SELECT signal. You can dig in and read about this in the technical documents at, but I'm condensing it to this one small fact for us.

To get 256 megabytes on a stick, they use two chip selects and out of that came the terms SINGLE SIDED and DOUBLED SIDED memory sticks. There was much confusion in PC LAND about this since many noticed that double sided sticks had chips on both sides! can't make money by sending you the wrong sticks. PNY is a generic (but good for most) brand that can't put single or double sided offerings on the shelf since support is non-existent.

Hope this explains it.


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