pc133 sodimm question

[griz145389]

I recently attemted upgrading the memory in my laptop to 2 sticks of 256 mb from the previous 2 sticks of 128 mb. After installing the new sticks the laptop failed to boot. All ram sticks are pc133 sodimm ram. After closely inspecting the ram, I see that the 2 sticks of 128 are labeled as pc133u, while the 2 sticks of 256 are labeled as pc133s. What does the u and the s indicate? Could that cause a compatibility issue?
Before anyone asks, as far as I know, the laptop supports up to 512 mb of ram. The manual states that it will accept up to 512, but the manual also states that is only uses pc100 memory, while it will in reality only run with the pc133. Also, the ram worked on a different laptop.

 

[FullertonAve]

It depends...

Do you know if the bios in your system supports two-rank SODIMM modules, or only single rank? If it's a single rank only system, do you know how your bios handles SPD data that it doesn't expect?

 

[BinarySynapse]

It's most likely a density problem. 128MB PC133 modules were generally low density chips, while 256MB and up modules are almost always high density. If the manual says PC100 only then it requires low density chips.

 

[griz145389]

It's most likely a density problem. 128MB PC133 modules were generally low density chips, while 256MB and up modules are almost always high density. If the manual says PC100 only then it requires low density chips.

The laptop has not worked with any pc100 memory I have put in it though.

It depends...

Do you know if the bios in your system supports two-rank SODIMM modules, or only single rank? If it's a single rank only system, do you know how your bios handles SPD data that it doesn't expect?

I do not know.

 

[Rage X]

What you don't understand is they also made High density PC100 modules. You need Low Density PC100 modules. This is definately the problem you are having.