Cheapest memory upgrade

C

cmreinke

New Member
I just received an old computer (HP Pavilion 7845), and would like to max out the memory. Since I received the computer for free, I'm trying to spend as little as possible on this. According to the HP website, the factory-installed memory is a 128MB SDRAM 168-pin DIMM 133MHz FSB chip (ASUS 810E processor, socket 370), and the maximum supported is 512MB. My problem is, depending on the website, I get a different recommendation on the "correct" memory for this processor (I'm looking for 2 256MB chips)--crucial.com shows PC133, but almost all other sites recommend PC100 (ex.: edgetechcorp.com). Also, I know that the memory should be unbuffered, non-parity, and non-ECC, but most sites recommend 32Mx64 and 16x8 chips. My question is how crucial are the last two specifications? According to pricewatch.com, PC100 256MB memory is only $21.99, but it's 32x72; the cheapest PC100 256MB that's explicitly both 32Mx64 and 16x8 is $16.00 more. Also, the cheapest is PC133 256MB is $23.00 for 32x72, but the cheapest that's both 32Mx64 and 16x8 is $25.00. If the PC133 won't give me any performance advantage, I'd just assume get the cheapest ($22) chips, IF they're compatible with my system. Otherwise, I'd just assume get the $25 PC133 memory (Micron Technology), which I assume should be completely compatible. Any suggestions?

-Charles
 
The maximum supported is two 256mb PC100 168pin for that model. That is the memory type for that model HP system there.
Memory
Component Attributes RAM (standard) 128 MB RAM PC100 Maximum 512 MB (2x256 MB DIMM) Speed 100 MHz synchronous Sockets 2 – 168 pins DIMMs Size 32, 64, 128 and 256 MB DIMMs Free DIMM Sockets 1 Pairs Required No Type Supported SDRAM, Intel PC SDRAM unbuffered DIMM specification, revision 1.0 compliant
http://h10025.www1.hp.com/ewfrf/wc/...product=61776〈=en&cc=us&docname=bph06462#N547
 
Thanx for all the help thus far. So it seems that the PC100 memory is the recommended type, but would there be any compatibility problems if I used PC133 instead? Wouldn't it just run at PC100 speed, at worst?

Also, how do I know for sure whether the memory is low or high density--isn't 16x8 (as opposed to 32x8) memory "low density"?

It seems that the PC133 32Mx64 16x8 memory is my cheapest option. The only problem I can see that it doesn't specify non-ECC, but even this should only affect performance, not compatibility, right?

Thanx,
Charles
 
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One site shows the differences seen with the different sizes of PC100 available for that HP model. Unlike DDR dimms the older boards were generally set to use one type only.
Memory SizeChip DescriptionMemoryStock PartNumberOEM PartNumber
64MB Module 8x64-100MHz PC100, 168p DIMM, 3.3v, Sync190ms-041D6802A
128MB Module 16x64-100MHz PC100, 168p DIMM, 3.3v, Sync13ms-006D6382AX
256MB Module32x64-100MHz PC100, 168p DIMM, 3.3v, Sync (16x8)160ms-029-HP1818-7496

http://configurator.memorystock.com/result.asp?mn=Pavilion+7845&modelid=20042

Boards sold independently for custom builds usually saw newer models were both PC100 + 133 could be used as long as they were not mixed.
 
The easiest way to tell is to count the number of chips on it. You need double sided RAM, or low density. PC133 will work fine. ;)
 
The main problem seen when going with newer memory other then specified by HP, Dell, Packard Bell and Epson at one time, and others is finding memory that is actually "backward compatible" to run PC133 on a PC100 system. DDR and DDR2 memories on the other hand see this more often since newer boards support the varying memory speeds like initially 133mhz, 166, 233, 266 and above for DDR, 333, 400, with DDR2 seeing 533mhz, 667, and 800mhz on the newest model and type boards out.

Older Proprietary systems saw boards designed to run on one type only where you went to them for any upgrades on memory and other hardwares.
 
You eun into problems when the memory installed isn't backward compatible. That has nothing to do with the quality of the brand used. :rolleyes:
 
OK--just an update, in case anyone is interested. I decided to go ahead with the cheapest 256MB PC133 memory that specified both 32Mx64 and 16x8 configuration ($26 each). I finally got around to installing the memory today and everything seems to work fine (BIOS and WinXP both recognize 512MB total memory), despite the fact that the two chips weren't identical. I was a little worried since one chip was a few mm taller than the other one for some reason. Anyway, bottom line is that everything works and I didn't have to pay $12x2 extra to get "the same thats already in it." :P

-Charles
 
So I'm assuming, because it specified 16mx8 that you got the double sided RAM? Which if so, that's a good thing... It's faster than high density RAM anyways.

Anyways glad to see it works. All's well that ends well.
 
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