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Needing advice on purchasing 256MB of PC100 SDRAM for HP Pavilion 6638

Hi Everyone:

       I have a friend who has an HP Pavilion 6638 with 64MB of RAM.  He wishes to upgrade to 256MB of PC100 SDRAM which brings me to the point of my question.  Can I order 256MB of PC100 SDRAM from any online store which offers it?  Or, will the RAM for this pc be proprietary, meaning I must order it from a specific retailer, like Kingston?

        Any information or suggestions regarding this post will be appreciated.  I look forward to reviewing everyone's feedback.

        Thank you

        George

       
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Gary Case
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Hi Gary:

        Thank you so much!!!  Incidentally, how did you use the 4allmemory.com in selecting the correct memory to purchase?  I am interested in this information for any future situations which may come up when preparing for RAM upgrades.

         George
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Hi

       Thanks for the followups.  Regarding the last comment about single sided versus dual sided RAM, does single sided mean there are chips on the RAM stick, but just on one side whereas, dual sided means there are chips on both sides of the RAM stick?  And, does this tie into the "density" concept of memory mentioned by Gary earlier?

        George
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Hi

        Just as a followup, I believe the single sided is referring to SDRAM and the dual sided referring to DDR.  But, I am not sure.

        George
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Hi Everyone:

       Thanks so much for the prompt and well thought out feedback to this post.  Gary, as always, I sincerely appreciate the extra care given your responses.  You always go that extra step to clarify or breakdown the technical aspects for which I am very grateful.  

       Thanks so much again for an outstanding and exceptional job!!!

       George
You're most welcome :-)
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examan

Yes as what garycase said, the single sided will have memory chips only in one side, while the dual sided will use both sides...

DDR is just an improvement type of SDRAM, it's original technical name is DDR SDRAM.. the main different between them is working voltage and a special technology in DDR that will transfeer the data twice in one clock ( SDRAM trransfeer data one time only in each clock ) and here why it called DDR ( Dual Data Rate )...

DDR2 in another case is another step of developement of DDR, supporting lower voltages ( 1.8 DDR2 vs 2.8 in DDR ) and supporting 4 data transfeers per clock...
As to: "does single sided mean there are chips on the RAM stick, but just on one side whereas, dual sided means there are chips on both sides of the RAM stick?"
In the "Way Back Machine" that was true (that's how the terms were coined), but it didn't last long because advances in memory technology soon allowed memory modules to be built in other physical configurations.

As to: "I believe the single sided is referring to SDRAM and the dual sided referring to DDR."
- NOPE!
---- SDRAM comes in single or double sided. It's not how the chips are positioned on the module (anymore), think of it as how the chips are WIRED (inter-connected) on the module.

Remember way back when you had to buy memory for Pentiums in matched pairs?
Double-sided is basically -wired- as a matched pair on one module.
(kind'a sorta, just a way to think of it..)

Other considerations the Experts have missed here are ECC vs non-ECC, Buffered or Unbuffered, and 3.3 volt or 5 volt.

Your full 'official HP' spec is PC100, 128 MB, non-ECC, Unbuffered, 3.3 Volt, 168 Pin SDRAM, Low Density, Single Sided.
It is one of the two most common types of 128 MB PC100. (Same spec but double sided is the other.)
PC133 with the rest of the specs unchanged should work ( 99+% likely) and may run a bit faster because it should be able to run at CL2 vice CL3 on a 100 MHz FSB system. (Assuming the system supports CL2, most do.)

Now, after all that::::
Your motherboard is a Trigem Cognac with an i810 chipset.
http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us&dlc=en&product=59365&lang=en&docname=bph05159
I've worked with one. (A friend had one.)
It was a happy camper with (two) 256MB PC133 low density modules. (Yup, 512 MB total.)
[ Crucial part number: CT32M64S4D7E.16TE ]

~~~ However:
As motherboards go, it's near the lowest of the low-end. ( E-Machines used loads of them.)
Also: Trigem boards are known to have problems with bad caps right up into the i845 chipset models.
(About Bad Caps) http://www.badcaps.net/ident/

I would not put money into it...
I would replace the motherboard with an i810 or i815 chipset based board that fits in your case. (Micro-ATX form factor I think.)
I'd go with Intel, Soyo, or DFI. They are only manufacturers I have not seen any Bad Cap issues with (yet) on socket 370 boards.
Your existing socket 370 CPU (and other system parts) will be compatible and a mainboard of that vintage could probably be had for under $25.
.