My computer says that I have 256 MB's of RAM, 4 x 64's. However when I physically removed each RAM to verify, two of the modules have the following data on them:
Kinsgton KTH-XU800/128
555243 K2
9902275-018.A00
My question is, does the 128 mean that it should be 128 MB's? The other two are the following:
HP1818-7743
64 MB RDRAM PC800/4 (dual)
Reorder P2144-63001
I want to double the present 256 to 512.
Thanks..

Is this a HP (http://www.phptr.com/articles/article.asp?p=30069&seqNum=8) computer by any chance.

The Kingston memory modules seem to be 128MB ECC and the HP ones 64MB NON-ECC. HP in the link above indicate that NON-ECC should be used, whether this is what is causing the mismatch or not. On some mobos the sequence of modules (larger before smaller or vice versa) can also be important. Check out your manual or on-line support carefully.

I think the best you should hope for is 384, not 512 ;). Make sure when you install them, you put the 128 sticks in the first bank. Often, if the smaller amount is in the first bank, the computer won't recognize the rest, as Paul mentioned.

The computer is a HP Vectra VL800 (P2074T), it's a freebie that I'm upgrading for personal use. I've tried every combination of using each memory in each bank, but the results are the same. I don't have the manual, but from what I've read, it will (should) accept the 512 MB's.

With anything less than all four modules in place it will not boot up. I'm not sure what the beeps are in the POST (I don't know the codes), but it beeps and will not boot until I put all back in.

I read about the ECC vs non-ECC memory, and they should all be the same. However, from what I've read it originally came with non-ECC, but will accept either, they can all be either, but not mixed. My OS is XP, will this make any difference?
Thanks...

The "128" on two of the modules could simply refer to the memory chips as being 128Mbit density. How many chips are on each stick? Are there chips on both sides?

With anything less than all four modules in place it will not boot up.
Of course not. RDRAM was designed as a more serialized bus architecture than normal SDRAM, thus if you want to install only 2 modules, you'll have to put RDRAM continuity modules into the other two slots. The continuity modules act as a sort of bypass to "complete the circuit" of the RAM bus and contain no RAM chips themselves (they're just blank filler sticks).

Thanks for the information, I just finished reading about the continuity RIMM's from the link above. As for the 128 on the modules, these RDRAM's only have chips on one side, and they are enclosed so you can't tell eaxctly what is on the module.

Ok, I found the problem. Google fixes all!

According to this (http://price.pricesaving.com/productprice_id_196586_computer-price-compare.htm), the mysterious "128" refers to the fact that the two RIMM modules came together in a 128MB kit. In other words, both of them = 128MB, not 128MB each. Also in that link, you'll see that the two Kingston RIMM's are ECC, so it's a safe bet that all are ECC (either that or ECC is not enabled).

The main site from that link above also suggests that you can indeed use up to 512MB per stick of RDRAM, provided you use ECC RDRAM (and why wouldn't you if you already have ECC). However, upgrading the RAM could prove to be prohibitively expensive if you use 256MB or larger sticks.

I understand now. Thank you all for your help, I guess the key word was "kit" in all that we've read.
Thanks again...

Hi,

First I thought you have 2 sticks RDRAM each 128 MB and two dummies to terminate the other two slot. But when I looked at your memeoy, Kinsgton KTH-XU800/128, I saw they are 64mb each so you are right, you have 4 X 64MB sticks.