HELP: need help about SDRAM

[slimzky]

my uncle requested me to fix his PC. its an P3 550mhz (slot 1), using VIA 6VABX2 mobo, & only 64mb of sd ram. he gave me money to buy 256 sdram but i forgot to check whats the frequency of the old ram.. (pc100)

i then brought 256mb pc133 srdam & put it into his mobo removing the old one.. when i boot up, it only detects half of the memory im not good when it comes to hardware.. i dont want to frustrate my uncle (although hes totally noob to pc).. i dont want to leave his pc runnin only at 128mb of ram when its supposed to be 256mb..

what shud i do? how do i setup it in CMOS?

[trickytwista]

strange how it detects half of it... you sure the board does support it? sounds like an incompatability issue

[ssmokee]

my uncle requested me to fix his PC. its an P3 550mhz (slot 1), using VIA 6VABX2 mobo, & only 64mb of sd ram. he gave me money to buy 256 sdram but i forgot to check whats the frequency of the old ram.. (pc100)

i then brought 256mb pc133 srdam & put it into his mobo removing the old one.. when i boot up, it only detects half of the memory im not good when it comes to hardware.. i dont want to frustrate my uncle (although hes totally noob to pc).. i dont want to leave his pc runnin only at 128mb of ram when its supposed to be 256mb..

what shud i do? how do i setup it in CMOS?

The short answer is you need a low density 256MB module. Nothing you can do in CMOS will fix this; it is a chipset/memory controller limitation. Low density 256MB modules should be easy to spot because they have chips on both sides, where high density modules should only have chips on one side. Some stores might still carry the older low density modules, but they usually charge a premium for them.

Other options include exchanging the 256MB module you have for 2x 128MB modules, or trying to find a used low density 256MB module.

[puntoMX]

With other words:

Now for example you have a 8 chip DIMM, you will need a 16 chip DIMM

Sometimes a BIOS update can help a bit, but most of the time it´s hardware...

[slimzky]

thnx for your reply guys.. i will try to look for 128 x 2 modules.

[nmX.Memnoch]

According to this site you need older EDO SDRAM to be able to use 256MB sticks.

http://www.resoo.org/docs/_hardware/th99/m/I-L/36011.htm

If you use standard SDRAM then you can only get a maximum of 384MB, which would be 3 x 128MB SDRAM sticks. With EDO SDRAM the board is capable of handling 768MB RAM, or 3 x 256MB EDO SDRAM sticks. Non-ECC EDO SDRAM is kinda hard to find anymore though.

[Maleko]

wen ive had only half a stick of memory working for me, the reason for it was the other half had died...so 256, half of it was dead....had it replaced, worked....was a while back

[puntoMX]

EDO RAM? eeuhmm, that is way back, 72 pins? I think we are talking here about 168pins?

It´s not the size of the dimm, it´s the "chip count" that is important: 256MB with 16 chips (double sided) or 128MB with 8 chips

EDIT: Just got 128MB PC133 DIMM with 16 chips in, they still "make" them

Edited March 14, 2006 by puntoMX

[ssmokee]

According to this site you need older EDO SDRAM to be able to use 256MB sticks.

http://www.resoo.org/docs/_hardware/th99/m/I-L/36011.htm

If you use standard SDRAM then you can only get a maximum of 384MB, which would be 3 x 128MB SDRAM sticks. With EDO SDRAM the board is capable of handling 768MB RAM, or 3 x 256MB EDO SDRAM sticks. Non-ECC EDO SDRAM is kinda hard to find anymore though.

The board manufacturers specs in a case like this cant really be trusted. For motherboards of that era it was common for the manufacturer to simply state that it doesnt accept 256MB SDRAM modules to avoid the flood of tech support problems resulting from people trying to use high density modules and only half the capacity showing up.

Im using a Via based motherboard that is as old as his (quite possibly older) and it is using 2x 256MB low density pc133 SDRAM modules (not EDO) despite the fact that it clearly states in the manual that the max installable RAM is 384MB. I have had 3x 256MB in there at one point in the past and that worked just fine too.

Edited March 12, 2006 by ssmokee

[nmX.Memnoch]

EDO RAM? eeuhmm, that is way back, 72 pins? I think we are talking here about 168pins?

There is such a thing as 168-pin EDO SDRAM DIMMs. Most of what you will find now is ECC though, which his board doesn't support. The very first PII boards that used the Intel 440LX chipset used them. Do some research.

http://www.pricegrabber.com/search.php?for...DIMM&topcat_id=

You also have to take into account that when the manufacturers original support specifications were released for those boards low-density 256MB PC100/PC133 DIMMs were a rarity (possibly not even publicly available at the time). They rarely, if ever, go back and update those original specification documents.

[puntoMX]

Yeah, your right:

http://www.oempcworld.com/Merchant2/mercha...8M-EDO-DIMM-ECC

Those ones are used in printers and some servers indeed, I forgot about it. But like you also say: "Most of what you will find now is ECC though, which his board doesn't support."