Inconsistent results after memory upgrade

[leelou]

Hello HP,

I had this machine with two 1GB dimms from hynix (1Rx8 PC3 10600U 9-10-A0). One in slot 1 and one in slot 3. Win7 64bit ran Ok and also I could run some live Linux OS'es, be it somewhat slow.
Then I bought 4GB to be put in slot 2. I followed the requirements in the manual and chose the kingston 4GB PC3 10600 CL9 240 pin dimm (partno KVR13N9S8/4).
Win7 tries to boot but soon returns the blue screen of death. Running live Linux results in the famous kernel panic.
So I tried several setups (different slots, different combinations). None of them (New stick alone or in combination with the older sticks) gets Win7 to boot. But, of I just put in the new ram, I can run a live Linux version, even copy the whole OS to ram.

I have absolutely no clue why this behavior occurs. The BIOS always recognizes all installed ram.

Could you please tell me if I have the wrong ram or why this is happening? And perhaps also advice how to solve this and which ram would be suitable ?

Your help is much appreciated.
Regards,
Mark

[erico]

It happened because you have mixed in a RAM module with different capacity that is also likely to have different timing (primary and secondary) and even possibly a different voltage requirement.

Purchase memory only in pairs of guaranteed compatible and identical modules, remove the original modules and put the upgrade modules in their place. 

From Crucial Memory

http://www.crucial.com/usa/en/compatible-upgrade-for/HP---Compaq/8100-elite-business-pc-%28sff%29

Take a look here as well.

https://www.google.nl/search?ei=__QTWrb_KMHZafLSmOAL&q=hp+8100+elite+sff+kingston+memory+upgrade&oq=...

[leelou]

Hello Erico,

Thank you for your time and quick reply, I really appreciate it.

Most websites in my country do not even provide the detailed technological specticifications required to obviously make a good decision on which RAM could be applied.

Although having read your reply, and just to be sure: I should not install 1 single bank of ram but always pairs? Is this the reason I get failures when I try to boot with just the New ram installed?

Since the crucial website you refer to also shows 512x8 memory that by itself shouldn't be a problem. So would that meen that if I buy another bank of the same ram, the problem would be fixed?

Sorry for the inconvenience of all my questions.

Best regards,
Mark

[erico · Accepted solution]

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@leelou wrote:
Hello Erico,

Thank you for your time and quick reply, I really appreciate it.

Most websites in my country do not even provide the detailed technological specticifications required to obviously make a good decision on which RAM could be applied.

Although having read your reply, and just to be sure: I should not install 1 single bank of ram but always pairs? Is this the reason I get failures when I try to boot with just the New ram installed?

Since the crucial website you refer to also shows 512x8 memory that by itself shouldn't be a problem. So would that meen that if I buy another bank of the same ram, the problem would be fixed?

Sorry for the inconvenience of all my questions.

Best regards,
Mark

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Your questions are intelligent and not inconvenient at all.

Always upgrade in pairs. Do not add more memory to existing RAM modules unless they are absolutely identical in all respects. Put memory in odd banks. banks O & 2 not 0 & 1. Do not mix different capacities or types( single-sided and double-sided)

If new RAM is installed and you get failures that means the memory is not compatible. Primary, secondary timings or DIMM voltage requirement does not match what the tables in the BIOS will accept.

If you buy an additional, absolutely identical module of the guaranteed compatible memory it will work.

"Since the crucial website you refer to also shows 512x8 memory that by itself shouldn't be a problem."

I see a 512 x 65module, I do not see a 512 x 8 module.

Crucial 4GB module

CT2347054

• DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 512Meg x 64 •
• upgrade for HP - Compaq 8100 Elite Business PC (SFF) system

 The "kingston 4GB PC3 10600 CL9 240 pin dimm (partno KVR13N9S8/4)" is incompatible with the motherboard if the PC will not boot with that module is placed in slot 0 and other slots empty.

[leelou]

Hello Erico,

You are absolutely right regarding the 512 x 64. Can't believe I still missed that even after you showed me how incredibly important those tiny details can be.

Thanks again for your explanation. I once tried again the run with just this new memory in slot 0 and Win7 does not boot. Strangly I can boot a live Linux distro and get it to run entirely in memory. In terminal I can see the full operational memory as well as in a type of task manager. That is odd, isn't it?

In any case, I really do need memory to be able to run any kind of OS without the concern of it possibly crashing. So I will take your advice, return this ram and see if I can find a shop that offers the couple of corsair or crucial banks that fit this model. I see kingston doesn't have any longer.

I appreciate your help Erico!
Best of luck to you and gratefull regards,
Mark