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Last reply by 10-03-2011 Unsolved
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Question on adding RAM to a PE 2900

Hello,

I have a PE2900 that has 8GB of RAM using 4 2GB Dual Ranked DIMMS.  I'd like to upgrade the memory to 16GB of RAM.   I was thinking about just getting two 4GB DIMMs to put in.  But then I saw this in the docs:

 

"For best system performance, all four, eight, or twelve FBDs should be identical memory size, speed, and technology."

 

What kind of impact will this cause to my server to mix 2GB and 4GB DIMMs?  Is that not wise to do?

 

Thanks.

 

Matt

 

Replies (5)
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We originally had 4 1GB DIMMS in our PE2900.  I fitted 2 x 4GB and removed 2 of the 1GB -  (you have to have 2, 4, 8 or 12 populated memory slots - 6 isn't a valid configuration) .The system runs fine with 10GB - however I did swap out the 2 lower banks for the new memory - so the 8Gb gets used before the. 

I'm sure you will be able to use 2 4GBs - but you may have to remove 2 of your original sticks, giving you a total of 12Gb.

 

 

 

2 Bronze
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If the system POST's it will work...but it is not the best configuration.  Physical memory should be matched or the memory sub-system will encounter frequent caching, less than ideal interleaving and more frequent wait states.  If you're going to spend money on an upgrade (rather than a new server), it's best to optimize the choices.

2 Bronze
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Well, I ended up talking to tech support and doing some research.  The configuration I was going to do, leaving my 4 2GB sticks in there and adding 2 4GB sticks, would not work anyway.  That was an invalid configuration.  I wanted to get to 16GB of RAM but you can't have 6 sticks in there of course.  So I ended up purchasing 4 4GB sticks and going to 24GB of RAM (4 2GB and 4 4GB).  I had no issue spending the money on the 4 4GB sticks, but I figured why not leave the 4 2GB in there and use them to get to 24GB of RAM.  Otherwise, they would have just sat on a shelf.  I asked tech support on two different occasions if it would cause a major performance problem and they all indicated it would not.    So far I haven't noticed any issues (this server is running VMware ESXi).   Is leaving those 4 2GB sticks in there really going to cause me a huge issue?  Would I be better off yanking them and just running with 16GB of RAM?

 

Thanks. 

2 Bronze
2 Bronze
740

It's not going to hurt you, it's just not the ideal config for running 24GB.  I'd stick with what you have now.

2 Bronze
2 Bronze
740

We had 4 2GB sticks in the server. - Slot 1,2,3,4

We did research and saw to "add in pairs" so we bought 2 4gb sticks.

We missed this in our research - "For best system performance, all four, eight, or twelve FBDs should be identical memory size, speed, and technology."

We put these new sticks in slots 5,6.

We boot and of course get the Memory Configuration Issue in POST.

Should we remove 2 of the 2GB Chips? giving us 12gb instead of 16?

The server is up and running and working.

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