# DIMM and UDIMM



## sean2008

please, can somebody tell me if DIMM and UDIMM are compatible? 
I'm trying to upgrade my memory, but for some reason the new RAM memory I bought this afternoon won't work with the slot I already had. Separately there working just fine, but my screen won't give any response when I try to start up my computer with the two of them. I'm wondering whether this could be a compatibility problem between DIMM and UDIMM, because the new memory I bought is UDIMM?
Please help, 'cause I'm getting pretty frustrated over here...

Thanks


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## PC eye

right off you mixed two different types of memory which essentially is a "no no" there. The fact that both work with only one dimm in means both are compatible but not with each other as one cancels the other out.

Whenever adding more memory or replacing memory you first want to match what you already have installed as far as type and generall speed but certainly timings and type to avoid problems. Now you have to choose which you will keep in and add more of that particular type hopefully identical.


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## tyttebøvs

pc eye, have you googled that?


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## PC eye

tyttebøvs said:


> pc eye, have you googled that?


 
Sounds like something you would do. I don't use Google in the first place. But then you wouldn't post anything useful and subject related anyways. 

You'll have to excuse the interruption sean2008 since some lack any common courtesy and would rather spend time trashing threads.


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## tyttebøvs

I'm not trashing. It was a hint.


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## StrangleHold

Other PC eye sayings.

Its a typo - misunderstanding - dont get it - missed something - In other words - I meant another chipset - I was explaining something else - keyboard key stuck - tombstones - some kinda of DDR support on the XP 3200- extra wide IDE cables - uninstalling USB drivers will crash windows - The 8mb. of unallocated space is a flaw in windows setup - change the subject  - hijacking threads  - slander attack.


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## StrangleHold

sean2008 said:


> please, can somebody tell me if DIMM and UDIMM are compatible?
> I'm trying to upgrade my memory, but for some reason the new RAM memory I bought this afternoon won't work with the slot I already had. Separately there working just fine, but my screen won't give any response when I try to start up my computer with the two of them. I'm wondering whether this could be a compatibility problem between DIMM and UDIMM, because the new memory I bought is UDIMM?
> Please help, 'cause I'm getting pretty frustrated over here...
> 
> Thanks


 
Tell me what so called UDIMM and DIMMS you have and what motherboard they are on. UDIMM just means unregistered.


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## sean2008

My motherboard is  ECS  RC415ST
It's an  Intel Pentium D 915
I want to have 2GB of memory on there.

But are you saying that they should work together? That there's no real difference between UDIMM and DIMM?


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## sean2008

Oh I forgot,
the memory I already had is  DDR2-667  MEADR422LA4701
the new one is  DDR2-667U MEADR422LA4701-08A6
they're both  pqi


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## tyttebøvs

DIMM is just the generic name. You have UDIMM, RDIMM, FBDIMM, SODIMM, etc.

UDIMM is what people in general use in their desktop pcs.


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## sean2008

Hey, I just solved my problem. I bought two identical Kingston slots and everything is working fine now. Apparently the two DIMM modules I had before were not identical ones. 
Thanks for your reactions and help


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## StrangleHold

The voltage and timming were probable way off from each other, with a little bit of bios tweaking they might have worked together. But glad you got it running.


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## PC eye

StrangleHold said:


> The voltage and timming were probable way off from each other, with a little bit of bios tweaking they might have worked together. But glad you got it running.


 
And a little voltage increase and such and then.... poof!  So that would be your advice? 

Funny how matched dimms always seems to work out.


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## TrainTrackHack

> And a little voltage increase and such and then.... poof!  So that would be your advice?


...you do realise some boards actually have separate voltage conrol for each memory slot?


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## StrangleHold

I have begin to realize that questioning PC eye makes about as much sence as bending over and running head first into a wall.


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## PC eye

hackapelite said:


> ...you do realise some boards actually have separate voltage conrol for each memory slot?


 
Are you going to recommend making changes like that to someone who lacks experience with memory to begin with? "oh just go in and play around with the voltages and you'll be fine!" right?!


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## TrainTrackHack

> Are you going to recommend making changes like that to someone who lacks experience with memory to begin with? "oh just go in and play around with the voltages and you'll be fine!" right?!


No, I'm just saying, setting voltages&such manually doesn't necessarily result in a *poof*, I wouldn't think it's be harder than checking the voltage requirements of individual sticks and then simply going to BIOS and set the volts. Just like learning violing or guitar, or migrating to Linux, or looking up some numbers and then typing them up on the computer, it's not really that trivial after all.


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## PC eye

hackapelite said:


> No, I'm just saying, setting voltages&such manually doesn't necessarily result in a *poof*, I wouldn't think it's be harder than checking the voltage requirements of individual sticks and then simply going to BIOS and set the volts. Just like learning violing or guitar, or migrating to Linux, or looking up some numbers and then typing them up on the computer, it's not really that trivial after all.


 
While someone accustomed to getting in there and toying around with things can see results that's fine for the more then novice. The main idea however when advising someone new is to point out a far more practical outline like recommending identical dimms that will see immediate results just like sean2008 ended up seeing there. 

And if you set memory that runs at 1.8v upto 2.2v you will likely see "poof!" when the memory gets cooked. That's called overvolting which can easily damage memory.


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## TrainTrackHack

> And if you set memory that runs at 1.8v upto 2.2v you will likely see "poof!" when the memory gets cooked. That's called overvolting which can easily damage memory.


Yes, yes, and the sky is blue...



> While someone accustomed to getting in there and toying around with things can see results that's fine for the more then novice. The main idea however when advising someone new is to point out a far more practical outline like recommending identical dimms that will see immediate results just like sean2008 ended up seeing there.


Sean got the problem fixed, so it's all good now. But everyone's a novice at some point, if they never try anything more "advanced" they ain't gonna get better... I can't see why a novice couldn't do this, whatever you do there's always SOME kind of risk, but oh well...


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## PC eye

The idea is to first have any novice first ask questions and be advised that they still have to consider risks of any possible damage. You wouldn't want to advise doing this or that to someone new and on a tight budget who is not in a position to simply run out and buy any replacement parts counting on what they have only.

Once you get into custom building and have the extra cash to spend then you can decide to try this or that and certainly ask questions on how to go about seeing it done from someone else with experience. That's how we all get started to begin with there. 

sean2008 did make a positive move when ordering a new pair of dimms and seeing working results there. That's from simply asking for help amd ordering one of the better brands of memory.


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## TrainTrackHack

> You wouldn't want to advise doing this or that to someone* new and on a tight budget *who is *not in a position to simply run out and buy any replacement parts counting on what they have only.*





> sean2008 did *make a positive move when ordering a new pair of dimms* and seeing working results there. That's from *simply asking for help amd ordering one of the better brands of memory.*


You do realise you're contradicting yourself... he ended up simply running out and buying replacement parts anyway, I can't see what practical difference it makes here.


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## tyttebøvs

The idea is also not to tell a novice that UDIMM and DIMM doesn't match, because they are different type of modules...


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## PC eye

PC eye said:


> right off you mixed two different types of memory which essentially is a "no no" there. The fact that both work with only one dimm in means both are compatible but not with each other as one cancels the other out.
> 
> Whenever adding more memory or replacing memory you first want to match what you already have installed as far as type and generall speed but certainly timings and type to avoid problems. Now you have to choose which you will keep in and add more of that particular type hopefully identical.


 


tyttebøvs said:


> The idea is also not to tell a novice that UDIMM and DIMM doesn't match, because they are different type of modules...


 
If you mix a performance dimm with value ram memory you will automatically see problems. That was one reason why you didn't see any reference to UDimm and Dimm mentioned since the problems was apparently a mismatch of types. I suspected that more then anything right off there.


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