I am about to buy a ram to upgrade my current ram. I bought one on
ebay and did not work because I get a single sided and my motherboard
will not read but half of it, even though my motherboard book says "
Support single and double density DIMMS" at page 2-12
I bought PQI PC133 single sided 168 pin 256mb ram

so did I misunderstood the book? I better ask some one who got the
experience. so please help.
my motherboard is Slot 1, Abit Bx6 rev.2 supports Four 168-pin DIMM
sockets support up to 1GB SDRAM module. the link has all the info
which will not make as much sense to me as to someone who know what to
look for,
I was not able to understand all whats in the book with my limited

I may get a good deal on a SAMSUNG 4x 256MB 256MB PC100 110958-032
Double Sided sided (9 chips each side)
80ns 3.3V 168PIN PC100 CL2
and wanting to know if I buy it, will it work fine?

thanks allot

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All 6 Replies

Your motherboard will use either PC100 OR PC133, CL=3 OR CL=2, unbuffered, non-parity, 3.3V, 32Meg x 64

There is a very good article which explains all of this in easy to swallow bites of information.


Most all manufacturers have a web page that will help you find compatible modules for your motherboard, and if you find RAM for sale else where, you can always call/email the manufacturer and ask them about the compatibility of the modules you've found, just make sure you have a make and manufacturer to work with. you might want to google the make and model first to make sure you have the correct information. The manufacturer will have at least two ways to contact them if you go to their site.

ECC memory (error correcting) is typically used in servers and is a little slower than non-ECC and found at places like ebay used, and I personaly wouldn't use it in my computer. The PC100 and PC133 is older memory and is getting harder to find, and more exspensive to buy, I had a slot A motherboard and discovered that for about $100. more than the cost of the PC100 RAM I could replace the mobo/RAM/CPU and had a faster, and new machine. Just a thought.

what is the different between 32Meg x 64 and 16MX72, can I use one in place of the other?

From your original post, where you talk about your system only using 128MB of the memory module rather than 256MB, it would seem that you are not using the BX6 V2.0 but the BX6.

Let's examine the board a bit more so you can fully understand how it works. From the manual:

The mainboard provides four 168-pin DIMM sites for memory expansion.. The DIMM socket supports 1Mx64(8MB), 2Mx64(16MB), 4Mx64(32MB), 8Mx64(64MB), and 16Mx64(128MB) or double sided DIMM modules. Minimum memory size is 8MB and maximum memory size is 512 MB SDRAM.

There are four Memory module sockets on the system board.(Total eight banks). In order to create a memory array, certain rules must be followed. The following set of rules allows for optimum configurations.

* The memory array is 64 or 72 bits wide. (Without parity or with parity)
* Support single and double density DIMMS.

From this information you can see that the the board can support both single-sided and double-sided memory modules; however, the maximum size for any single memory module is 128MB. This is why your 256MB memory module is only being used as a 128MB module. So, don't try to use anything larger than 128MB, since anything more than that will not be utilized.

A memory module with a configuration of 32Mx64 is a non-ECC memory module with a total capacity of 256MB (32 * 64 / 8).

A memory module with a configuration of 16Mx72 (the 72 represents that the module has extra parity information for error correction (ECC)) is a ECC memory module with a total capacity of 128MB (16 * 64 / 8).

As stated before, a memory module with ECC shouldn't be used for a standard desktop system, it isn't necessary and may hinder performance. Neither of those two choices you listed should be used: the 256MB non-ECC memory module is too large to be properly supported by your motherboard and the 128MB ECC memory module has ECC, which shouldn't be used on a standard desktop system. If you want a total of 256MB or memory on the system, I recommend that you get two standard 128MB (16Mx64) PC100 memory modules.

for sure, I have bx6 rev.2, I looked at google images and mine has 2 ISA where bx6 has 3 ISA slots, and they look quite different.

That is very odd then. I haven't worked with systems of that age for a long time now, so my troubleshooting skills for those machines may be shot.

It's possible that the problem is that you are trying to use a PC133 module when the board only supports up to PC100. It's true that the modules are backwards compatible and will run at slower modes, but that backwards compatibility sometimes creates odd situations.

I am trying to understand the point about the configuration mentionedin my original post (Unbuffered 16MX72 CONFIGURATION) and the
explanation in your post

A memory module with a configuration of 32Mx64 is a non-ECC memory module with a total capacity of 256MB (32 * 64 / 8).

A memory module with a configuration of 16Mx72 (the 72 represents that the module has extra parity information for error correction (ECC)) is a ECC memory module with a total capacity of 128MB (16 * 64 / 8).
[end quote}

the memory I mentioned is 256 but your explanation suggests that it should be 128. unless your explanation should interpreted (16MX72 / 8 = 128 per bank) i.e. if the memory is double sided which means 2 banks per module then 128 X 2 = 256, please clarify.

under the "memory configuration page" in my motherboard manual, there is a table which I am not sure what to make off.
to save typing, here is the relevant part
Type_Tech_Depth_Width_SS _ DS _Addressing_Row_Col_Banks_Min_Max

SD___64M_16M___ 4__16M_32M_Assymtrc_14__10___2_128M_256M
Ram _2

the next line is the same except the (Tech__64M 4 Bank, Banks__4 )

does this mean there is a 2 Bank "sided" and 4 Bank modules, is Bank means a side or a side can be broken up to several banks. could some one explain. i.e would 16Mx72 work in my motherboard?

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