RAM Compatibility

[Spain]

Hi,

Does anyone know if PC100 and PC133 are interchageable? I recently for a PC133 ram for my Dell computer that only takes PC100 and it's not working. I saw a lot of RAM out there that says they're PC100/133 and that's why I thought they can be used interchangeably, but my computer wouldn't power on after I put in the PC133 in there.

Any ideas?

Thanks!

Spain

 

[cdogg]

That shouldn't be your problem. Faster RAM can be used in slower systems, but not the other way around. If you had a system that required PC133, then PC100 wouldn't work. But in your case, PC133 should work just fine.

You need to check the amount you added. Can the mobo support this amount? I don't recommend using more than 256 MB of RAM unless you're running Windows NT/2000/XP.

~cdogg

 

[paparazi]

cdogg is perfectly correct when saying that PC133 is backward compatible and SHOULD work with a system that currently uses PC100, you notice I use the word Should! fact is for some reason some boards just don't like the faster ram and just won't work!! there doesn't appear to be any particular reason for this but I have seen it many times. Only thing to do is to see if you can exchange the PC133 for 100, it might actually cost you a little more to do this but it could be the only thing to do to get the board to recognise extra ram!
cdogg is also right in saying you may not actually benefit by having any more than 256mb ram if you are using windows 95/98 as they do not utilise large amounts of ram efficiently. Martin

 

[Jakespeare]

Casual input:
There is a valid reason why NEW (say, PC133) RAM won't work on an OLD (2-years old, or older - just an average number here) mainboard:
RAM DENSITY.
The BIOS may not be able to recognize the LARGER SIZE RAM CHIPS, aka, Higher Density RAM.

You take a stick of PC100 / 128 MB RAM, from 2 years ago, and the RAM has modules ( a total of 16) on both sides; that means, the modules are 8 MB's apiece.
Now, you look at a new module of 128 MB RAM, and it only has RAM Modules on one side,,,,,,, 8 x 16 = 128, but the RAM Modules are 16 MB modules and not compatible with the OLD mainboard.........

It might be that you could take a stick of PC133 / 128 MB RAM from last year, that is the 16 X 8 configuration, with the 8 MB modules and it would work in that old Dell (or whatever mainboard you have).
It is possible, (I'm totally non-comittal on this) that if you FLASH the BIOS you can then run newer RAM.

***** facts from the field *******

 

[sharper]

I've had experience (I bleedin bought one) with intel boards with 133MHz FSB that ONLY accept PC100 RAM. I bought PC133 RAM at the time as the vendor assured me that it would work. However, on opening the Motherboard box, out fell a bright yellow sheet saying that "This motherboard only supports PC100 ... blah...blah...blah"

This Intel board was based on the cc820 chipset (I think), and is less than a year old (I think, about)....

Anyhow hope it helps...

Sharper

 

[Ecaboodle]

Would also check for Dip switchs on the motherboard. A board i bought 3 months ago still has switchs on the board. If you can't fix it in 20 call someone who can.

 

[ceh4702]

This is a problem that can be avoided.

http://www.crucial.com

has a memory selector that lets you enter the manufacturer/model of your computer/motherboard and determine what kind of RAM they have to sell you that will actually work in your computer.

This is a lot better than a one size fits all approach.

Here is an example of what I mean:

I purchased an A-Open motherboard AX59PRO and an AMD 300 K6-2, and when I tried some pc-100 RAM it kept giving me a BIOS checksum error. The problem was that the memory just was not compatable with the motherboard. I put some Micron PC100 memory in it and it worked just fine. I put the other memory in another computer and it worked just fine too.

I have been buying Micron memory ever since and have never had trouble with it. I recommend buying the memory your computer was designed for. Why buy cadilac memory to put in an old jalopy? It is questionable buying anything for a computer that is over 2 years old. For instance, you can buy a new hard drive but it will only go as fast as the computer you put it in is designed to go. If you do not like my post feel free to point out your opinion or my errors.

 

[murcielago]

I have had a very wierd problem. When i change something in my motherboard i get this beeping sound from my motherboard. LONG BEEPS. Then i change things back and i get the same beeping. But what i have to do is take out the ram and put in another stick. This has happened several times to me. And what i ended up doing is putting in PC100 RAM it's VM RAM. But my questions is, could a RAM company be incompatible with a motherboard. I have a IWILL KD266 and the RAM that gave me the problem is INFINEON, and i tried my PC133 256mb and i tried a PC100 64mb and it didn't work. But the PC100 Vm ram works fine.. Does that make sense.
thnx

 

[cdogg]

It is possible that certain types of PC100 and PC133 SDRAM might not be compatible with certain motherboards. The vendors I have bought from in the past have always asked me what mobo I owned and double-checked to make sure it was compatible. Generally speaking, Micron, PNY and Kingston tend to work universally better than others I've used.

 

[ceh4702]

RAM Isnt necessarily interchangable.

You may be able to use PC-100 RAM in a motherboard designed for PC133 ram and you may be able to use PC-133 in a motherboard designed for PC-100 RAM. Usually if you can do that, all the RAM in the system runs at the slowest speed. That is why it is a waste of money to mix them up.

Things to look for:

1. What is the voltage requirement for the RAM?

2. Will the Bus the ram is on run at a slower than maximum speed?

3. Will a computer designed for PC-133 ram run at PC-100?

These questions are Motherboard specific. Not all motherboards will run at slower speeds to achieve backward compatability. If you do not like my post feel free to point out your opinion or my errors.

 

[cdogg]

ceh4702,

Sorry, but I don't think you can ever force the bus to run at a slower speed without underclocking. If you insert a PC-100 module into a PC-133 system, it will not run. You can, however, usually put PC-133 module into a PC-100 system assuming the memory density is compatible.

Perhaps you meant to say it the other way around!!