Question : Problem: PC133 memory upgrade

I have an older Gateway computer (Raeman BTO 600) which is a Pentium 3. It has only 128Mb of Ram and I want to upgrade to 256Mb or more.

The motherboard has 2 memory slots (1 occupied and 1 empty). In one of these slots I have a 128Mb DIMM made by Hyunday part# HYM76V16635 HGT8-HSM. After consulting a Parts catalog I found out that this memory stick is a PC133U-333-542, which means that it is PC133Mhz 168-pin SDRAM compatible with (8Mx8) density.

My questions are:
1. Can I assume that if I buy another 128Mb stick of different density and brand (i.e. 16Mx8 or other) it will work with my Hyunday stick as long as it is PC133 SDRAM?

2. If I get a non-resgistered non-parity stick, is it possible that it will work with my older one regardless of the possibility that my older may have the parity error-check feature?

3. Do DIMMs allow you to mix different capacity sticks in the same motherboard? Example: My old 128Mb in one slot and a new 256Mb stick in another slot?

PS- Please assume that I will keep the old stick.

Thanks.

Answer : Problem: PC133 memory upgrade

1) Some RAM is high density and some motherboards can't read them correctly.  Usually, the symptom is only half the RAM shows up.  If you use the configurer at www.crucial.com, they will guarantee that the memory works in your machine.  High-density RAM is an issue with PC-100 and PC-133 RAM and older motherboards.

2) You should not mix ECC and non-ECC memory

3) You can mix different capacity DIMMS.  The newer DDR memory and dual-channel arrangements care about similarity, but you should be ok.