Motherboard is not recognizing all the RAM


The origional memory i bourght for this computer was 1 module of 256mb , pc133 single sided sdram , my computer only recognised 128mb . So logically thinking if i fitted another 128mbs i would end up with 256mb this wasn't the case, i ended up with 196mb oviously it was only recognising half of the new memory!! I carried out a system check with an online company and going through the details it bourght up the frequency of this memory was pc100. By this time i was getting really pissed off so i got 2x128 sync 100mhz pc100 double sideded sdram memory off a mate, the memory was fitted and my computer recognised the 256mbs. I carried out the system check again and the frequency now says pc125, ive never heard of pc125 , can this be right and will my system be ok with this??????What is this frequency all about???


This question was answered on November 6, 2004. Much of the information contained herein may have changed since posting.

Ok, base RAM of three different speeds is likely to cause more long-term problems than less of one speed.

In theory you can run that combo, if all were 133 or 100 except for the 125 (which IS an OC'd PC100 using the faster modules used for PC100 mfr also), BUT, the CPU's base is 100 and ideal for that age of system is a 1:1 RAM base to CPU Base I would pull the PC133 and try in another system, if it does not work there it is defective.

Only way I have gotten this combo to work, and I do NOT know if it will work in YOUR system specifically, is to put then in teh following order:

DIMM0 (possibly DIMM1 if lowest numbered DIMM slot is numbered DIMM 1): PC133 module

DIMM1 (next higher number): PC125 module.

DIMM2 (next higher number): PC100 module.

If this order results in a no-boot then the PC133 is defective or damaged, about 70% pobable Only way to confirm totally is on another machine what has a motherboard that takes a PC133 per that motherboard's manual.

IF the PC133 works this way, best way to OC would be to use all PC133 memory and OC base of CPU to about 115-125 That way, RAM is not pushed beyond max Withotu very agressive cooling, the PII is unlikely to run at 533, have seen them run at 500 MHz with faster RAM modules And run fairly stable So yes, some OC possible, but

depending on the board, if it's a high density ram module, one of three things will (or won't, as the case may be) happen:

1- It'll only see half the stick

2- It won't see the stick at all

3- It'll refuse to POST with the stick in it

DIMM 1 = pc133 128mb (8 chips)

DIMM 2 = pc100 256mb (8 chips, can see only 128mb)

DIMM 3 = pc125 64mb (16 chips)

You can use high density RAM in a BX system, it's just that it'll only see half of it AFAIK there is no PC100 that is high density, so the salesman was yanking your chain and sold you some PC133 as PC100 PC125 is odd, I've never heard of such a speed (though I have heard of PC150) In any case, I'd have to say no on the overclockng due to low quality of system components.

The 440BX doesn't have PCI/AGP locks, and unless you've got a 1/4 frequency divider jumper on your motherboard your PCI will get too fast for most cards to handle at 133 Your Voodoo3 will not be able to handle the 2/3 multiplier at 133FSB, so you'll need to upgrade to a GeForce 2/3 Your best bet for RAM is getting some PC133 cas2 low-density modules, 3x256MB, 16 chips per module Northbridge cooling will also be useful At least lap your greenie and put some thermal grease on it (assuming you have a green Northbridge heatsink).

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Posted by Jerry of Katharine Gibbs School - New York on November 6, 2004