PC133 memory on a PC100 MB?

[Armitage]

I reccomended this to a neighbor who is upgrading their PC. PC133 was actually a little cheaper then PC100, and I figured it would just be underclocking the memory. Now that she got the memory ... it doesn't work! System won't even boot with it. Any ideas what the problem is? Anybody want to by some 128MB PC133 sticks?
Thanks

 

[AWhackWhiteBoy]

If its an older pc100 system its most likely that the motherboard doesn't support high density SD-RAM chips. However if you bought 128meg sticks it should work,but there is a chance they are in fact high density. do you have a link of where you bought them from?

 

[Bovinicus]

The actual speed of the memory will not be a problem. The motherboard will just force the memory to operate at 100MHz. If the price difference is none or negligible, then going with a higher speed memory helps assure stability. You may have to adjust the settings via the CMOS setup program.

 

[Armitage]

I reccomended NewEgg to her, but not sure what brand she bought. The system is a SlotA box, so fairly old.

If that's the case, I may be able to swap the sticks with the ones on one of my rigs. They are almost certainly low density I'm guessing (128MB Mushkin bought in 2000).

 

[Armitage]

Originally posted by: Bovinicus
The actual speed of the memory will not be a problem. The motherboard will just force the memory to operate at 100MHz. If the price difference is none or negligible, then going with a higher speed memory helps assure stability. You may have to adjust the settings via the CMOS setup program.

Yea, that was my going in position .... I'm going to go over there tonight and poke around the bios a bit.

 

[AWhackWhiteBoy]

Yea, try at least one from your box to see. Its a fairly common problem with those older PC100 chipsets.

 

[Zepper]

Yeah, sometimes they can't read the Id chip on the module and a BIOS update might fix it - but often this can be bypassed by setting the memory parameters manually (instead of reading the spd ROM). But other times it's a chip density problem and you'll need a different module.
.bh.

 

[bob4432]

i had the same problem on a p3 hp computer i was working on. as soon as i put pc100 in, which was more expensive, it worked ok. with the pc133, no boot, even after i updated the bios, cleared the cmos...

 

[tallman45]

Some pc133 sticks have written right on the box that they are not compatable with pc100 systems. I have had some that would not work, and some that have. The ones that I had that did work were from Kingston, but you will have to check.

 

[Jeff7]

Originally posted by: ergeorge

Originally posted by: Bovinicus
The actual speed of the memory will not be a problem. The motherboard will just force the memory to operate at 100MHz. If the price difference is none or negligible, then going with a higher speed memory helps assure stability. You may have to adjust the settings via the CMOS setup program.

Yea, that was my going in position .... I'm going to go over there tonight and poke around the bios a bit.

Find out the chipset too - it seems that Intel chipsets have had more problems with high density RAM, at least in my experience.

 

[pdn]

Originally posted by: bob4432
i had the same problem on a p3 hp computer i was working on. as soon as i put pc100 in, which was more expensive, it worked ok. with the pc133, no boot, even after i updated the bios, cleared the cmos...

Also check and make sure that your not going over the limit of RAM that the board can handle! Some older PC100 boards aren't rated to run more than 256MB. Go to the boards web site to find that out or if it's an OEM pc try Crucial and find your PC listed and it will give that information to you. It hasn't let me down yet.

 

[RandomFool]

i had this problem way back on one of my old computers, eventually i gave up and forgot about it. Later i got the ram working when i upgraded my mb. Apparently my motherboard just hated pc-133, it was an FIC SD-11 with a 750 slot athlon, i believe i still have it somewhere around here.

 

[kuritadelta]

Originally posted by: ergeorge

Originally posted by: Bovinicus
The actual speed of the memory will not be a problem. The motherboard will just force the memory to operate at 100MHz. If the price difference is none or negligible, then going with a higher speed memory helps assure stability. You may have to adjust the settings via the CMOS setup program.

Yea, that was my going in position .... I'm going to go over there tonight and poke around the bios a bit.

This used to be true.. but this changed with newer versions of ram chips... PC133 is not backward compatible with PC100 anymore.. Latest PC133(feel funny saying latest to SDram) will not work on PC100 system.