Help! 1/2 of memory upgrade is missing.

[MplsBob]

I have been suffering along with an old PC that contains an ASUS TX97-E motherboard with an 200MHz K6 AMD processor and 128MB of EDO memory.

I replaced the EDO memory with two 128 MB DIMM chips. The memory works just fine, but the computer "sees" only 128MB, not the expected 256MB.

The replacement memory has a part number of M366S1654CTS-C7AQ0 and is labeled as "128MB Sync PC133 MHz CL3 168 Pin SDRAM Samsung".

There are only two slots for DIMM memory and they are keyed, so it's a little hard to screw that up. Also, the ASUS manual indicates that the motherboard's memory max is 256MB.

The Bios startup display indicated memory present in rows 1 and 3, which seems a bit odd.

I am stumped.

Have I just wasted $40?

I am sure that several of you have the answer, so here is a hearty and heartfelt "Thanks to All of You" in advance.

 

[minendo]

Are the ram chips single sided or double sided?

 

[Mday]

yes you did waste $40. either one of the sockets is broken, or the mobo is too old. see which dimm isnt getting recognized, or only 64MB is recognized if you have one of the new dimms in.

http://www.baber.com/baber/411/asus_tx97_e.htm is some specs.

this board is based on the 430TX chipset, for those who dont know...

 

[MplsBob]

All of the chips are on one side of each card.

I am not sure if this answers your question.

 

[MplsBob]

Mday:

You said: yes you did waste $40. the motherboard is too old to recognize the 256 MB dimm.

I don't understand your reply. Each DIMM is 128MB and the ASUS manual for that motherboard indicates that the memory max is 256MB.

 

[MplsBob]

Iwill have to power down to run the checks you are suggesting Mday, so I will be off the air for a few minutes.

 

[Chaotic42]

From Crucial.com:

Motherboard Info:

* Chipset: Intel 430TX
* Supported DRAM Types: FPM, EDO, and SDR SDRAM
* SDR SDRAM Frequencies: PC66
* DDR SDRAM Frequencies: Not Supported
* RDRAM Frequencies: Not Supported
* 72-pin SIMM Banking: 4 (2 banks of 2)
* 168-pin DIMM Banking: 2 (2 banks of 1)
* 184-pin DIMM Banking: Not Supported
* 184-pin RIMM Banking: Not Supported
* 232-pin RIMM Banking: Not Supported
* Module Types Supported: Unbuffered only
* Max FPM: 256MB
* Max EDO: 256MB
* Max Unbuffered SDR SDRAM: 256MB
* Max Registered SDR SDRAM: Not Supported
* Max Unbuffered DDR SDRAM: Not Supported
* Max Registered DDR SDRAM: Not Supported
* Max RDRAM: Not Supported
* Error Detection Support: Non-ECC only
* AGP Support: Not Supported
* Max Component Density: 64Mb

--

The bold thing is what you have to look out for.

 

[Mday]

sorry, i kept typing the wrong thing, and editted a few times... but what is there now is what i intended to say.

the 430tx chipset is OLD. it was poorly designed, intel made decisions which caused it to suck in terms of memory handling (the 430 series) even in those olden days.

anyway, as for the 64Mb limit, it's the density of each chip. so, having 8 of those 64Mb chips means 64MB total for the module. if your DIMM has 8 chips and 128MB of RAM, then the density of each chip is 128Mb, which is larger than the 430tx can do.

 

[MplsBob]

I think I have stumbled across the answer in the ASUS manual for the motherboard.

It makes reference to the fact that the hardware is expecting memory on both sides of the card and my cards have memory on only one side.

If that is so, then two DIMMS with 64MB per side would equal the max configuration of 256MB.

So, I suspect the hardware is not wired for anything beyond 64MB per side, that would result in the BIOS reporting only 128MB total.

I am out $40 to learn this piece of arcane knowlege for a nearly extinct motherboard.

Asi es la vida (such is life).

Many thanks to the two of you for helping out with this. Both of you surprised me by the way you quickly recognized the implications of this out-of-date card.

 

[Blastman]

The older m/b?s will not recognize the newer high density ram modules (with 256mbit ? chips)

I have an older 256MB SDRAM module, it is double-sided with 16 chips. The newer 256MB modules only come with 8 higher density chips on one side and if you use them in some older m/b?s only half of it will be recognized.

My old Celeron 333 is like that. 3 memory slots, maximum 384MB which means only 128MB (low density chips) per memory slot.

Unfortunately it is quite a bit more expensive to manufacture a 256MB memory module with the lower density chips because for a 256MB module it takes 16 low density chips (using both sides) opposed to only 8 chips if the higher density modules are used. The lower density 16chip modules also cost more than the newer high density modules.

From a computer store ?

DIMMS 168PIN 128MB SDRAM (133MHZ CL3) PC 133 (8 CHIPS) $52.00
DIMMS 168PIN 128MB SDRAM (133MHZ CL3) PC 133 (16 CHIPS) $60.00
DIMMS 168PIN 256MB SDRAM (133MHZ CL3) PC 133 (8 CHIPS) $60.00
DIMMS 168PIN 256MB SDRAM (133MHZ CL3) PC 133 (16 CHIPS) $97.00