Hi StJames888, 

Your system supports maximum memory of 4 GB in case of 32-bit Operating System and 24GB in case of 64 bit Operating system. To get the maximum memory, you would need to install 6 modules of 4 GB each. The memory has to be installed in pairs of 3. You would need to install similar memory modules on slot 1,3 and 5 and another matched memory modules in slots 2,4 and 6 to upgrade the memory of computer. 

Please reply for further clarifications. 

My system is 64-bit. I have three (pairs) of the memory shown below. Two pairs are installed, the third pair is on the way. In other words, I'll have three pairs of two, not two pairs of three. Will that be a problem?

Cancel all of that. The post above shows laptop memory from a different order. Sorry for the wild goose chase.

If the existing modules in slots 1-4 all match, take 3 of them and put them in slots 1,3,5.

Buy 3 new modules that are a match amongst themselves and put them in slots 2,4,6.

You'll end up with one spare module from the original set of 4 which you can save as a backup for slots 1,3 or 5.

I have the same system and memory and the same issue.  Not mentioned above is that the manual also says:

CAUTION: If you remove your original memory modules from the computer during a memory upgrade, keep them separate from any new
modules that you may have, even if you purchased the new modules from Dell™. If possible, do not pair an original memory module with a new
memory module. Otherwise, your computer may not start properly. The recommended memory configurations are:
Matched memory modules installed in DIMM connectors 2, 4, and 6 and another matched memory modules installed in DIMM connectors 1, 3, and
5.

Doesn't the suggested solution violate this?

Thanks to all who respond.

Alan

BTW, looking to my upgrade path,  is it acceptable to have  a matched trio in 1,3,5 and either a single in 2 (with 4 and 6 open) or matched in 2 and 4 (with 6 open)?

Very kind of you to reply, Ron. Thanks.

I am confused and I think it revolves around the meaning of "paired" and "matched". When I read "pairs" of modules and looked at the pictures of the slots, that meant to me sets of two, like pairs of shoes.  So I thought they were referring to the sets of two modules (1&2, 3&4, and 5&6). What you are saying is that "pairing" in memory parlance refers to "grouping" and in this case means "paired" sets of three.  Right?  So can put 3 of my four existing 2GBs in 1, 3 and 5 and buy three new 4GBs for 2,4 and 6?

Thank again for your time.

Alan in NJ

Not sure what you're questioning about my solution, but I don't believe it violates the recommendations in the manual.

I said to put 3 existing modules, assuming they're exactly matched, in slots 1,3,5 and to buy 3 new, matched modules and put them in slots 2,4,6.

Are you perhaps being confused by "do not pair an original memory module with a new memory module"? That only means not to mix old and new modules in paired slots (eg, 1,3,5), not that you can't have matched old modules in 1,3,5 and new, different, but matched modules in 2,4,6.

Am I missing your point?

Yes, it is confusing.... 

My reading of "do not pair an original memory module with a new memory module" is "do not use an original..." in the same bank of slots (eg, bank 1=slots 1,3,5 and bank 2= slots 2,4,6). But they must be a match pair, if you only have 2 modules, total, in slots 1 and 3.

I gather you have 3 identical modules in bank 1 (slots 1,3,5) and one that's identical to the other 3 in bank 2 (slot 2). Is that correct?

So I would think it's ok to keep 3 originals in bank 1 and add one new module to slot 2. But does that gain much unless that one new module is much bigger than the old one it replaces?

Keep in mind if you only put a new module in slot 2, if you ever decide to increase RAM even further, that "new" module in slot 2 will have to be replaced to match whatever you now decide to put in slots 4 and 6.

Totally confused now? Me too! :emotion-5:

The Studio XPS 435T/9000 has a memory controller that is designed to interleave the memory locations across three identical memory modules in order to speed up data transfer.  If you have three matched modules installed in the correct memory slots, you should be able to see if your computer is working in this optimum mode by looking at the System Setup (F2 during the self test screen).  The information on the memory should tell you something like working in tri-channel mode.  If the modules are not sufficiently matched, the memory works in single channel mode, slowing the computer down a bit.

The computer will also work in dual channel mode if you have a matched pair of modules in slots 1 and 3.  If you place a second matched pair in slots 2 and 4, I believe it will continue to work in dual channel mode.  I'm not sure what happens, however, if you have a matched triplet in slots 1, 3, and 5, and a matched pair in 2 and 4.  I'm thinking that if you don't have the proper configuration for matched pairs or matched triplets, the computer drops to single channel mode.

You won't harm the computer by trying, however, and examining the memory operation in System Setup will tell you how you're doing.

You can download a utility like the free CPU-z to see what's in what slot (look on SPD tab in CPU-z). I'm guessing it's in 1,3,5 and 2 but I don't always use the same logic as Dell. :emotion-1:

You can buy 3x4GB for ~$105 or 4x4GB for ~$160. from Crucial for this system. They guarantee it'll work or they take it back.

Ron and Jack:

Again, let me begin by thanking you both for your time.

My current configuration is how I bought the computer from Dell: 4 x 2GB, presumably in 1,2,3 and 4? Or could it be 1, 3, 5 and 2? I guess I'll have to climb under the desk and open it up and look.  

I am just trying to figure out the best upgrade path that allows me to try something between the 8 I have and buying 6 new 4GBs (~$300).  From what you guys are saying, buying three 4GBs and leaving three 2GB (in 1,3,5 or 2,4,6) would be a good first step. Do you concur?

Thank again.

Alan

Ron:

CPU-z says 1,2,3 & 4 and dual under Channel #.  This is beyond my computer literacy, but would Dell have sold me the system with a memory configuration (dual) that didn't take advantage of the system's capabilities (tri)?

It would seem that the smart thing would be to buy 3x4GB for 1,3,5 and move 3x2GB to 2,4,6.  If that's insufficient I can then buy 3 more 4GB.  If you care to comment, I'd be interested to know  if you agree, but you've devoted enough time to me already so I understand  if you care not to.

Thanks again.

Alan

Sounds like a plan to buy 3x4 GB for slots 1,3,5 and move 3x2 to slots 2,4,6.

Post back and let us know how it works.

Will do.

Alan