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clarkey1984
Posts: 1
Member Since: ‎02-18-2014
Message 1 of 2 (221 Views)

DC5100 SFF and RAM...

Hi, im attempting to upgrade my machines memory from 2GB to 4GB, but im having problems.

 

This is my machine,  http://h18000.www1.hp.com/products/quickspecs/productbulletin.html#spectype=north_america&type=html&...

 

I am running windows 7 ultimate sp1 x64 edition.

 

Reading the overview on the above link it says that the fastest memory supported is pc4200, however im of the understanding that if faster RAM is fitted (pc6400 in this case) then it will simply run at the lower speed and so wont cause a problem, backed up by the fact that up until now i have been running 2x 1GB Kingston KVR800D2N5/1G, PC2 6400 sticks with no problems.

 

Before the upgrade i had 2.0GB detected and all of it was usable, the hardware reserved amount of memory was 1mb, i figured its so low because the onboard grpahics is disabled as im running an ATI HD5450 SFF card.

 

I have now added 2x 1GB Kingston KVR800D2N6/2G, PC2 6400 sticks to the system, and im having some strange outcomes...

 

Im now getting , RAM detected by windows in computer > system 4.0GB (3.12 GB usable)
resource monitor shows 905mb as hardware reserved.

 

OR...

 

RAM detected by windows in computer > system 4.0 GB (2.75 GB usable)
resource monitor shows 1282mb as hardware reserved.

 

 

It changes from one to the other when i boot up the machine, seemingly when it feels like it, i get a black screen just after the HP splash screen that says

 

"the following configuration options were automatically updated:

Memory: 3200mb"

OR

"Memory: 2816mb"

 

This seems to me that the BIOS cant make up its mind of how much RAM it wants to reserve for hardware, and so changes its mind, although the question here is what it is reserving this memory for,  as it only needed 1mb when i was running half the amount of physical RAM, why would it need more?

 

I have also borrowed some smaller RAM (1x256mb and 1x512mb) and tried various combos including 2.25gb, 2.5gb, 2.75gb, and also running just one of my new sticks so im at 3.0gb, and all of the above combinations allocate only 1mb to hardware reserved.

 

I then tried running 3.0gb and one (either the 256 or the 512)  sticks together,  and got the following from computer > system

 

3.25 GB (3.12 GB usable)

 

3.50 GB (3.12 GB usable)

 

To me, this is acting exactly like a 32 bit OS would when you try and add more RAM.

 

I have so far...

 

Unchecked the max memory option in msconfig, checked in the bios and ensured that the intel graphics adapter is disabled, reset the CMOS, loaded the default BIOS setup, checked to make sure theres no memory mapping options in the BIOS (there arent) and removed and refitted the RAM in near enough every combination that i can think of, and regardless of what i do, i cannot clear 3.12GB usable.

 

The only thing i did read about that i havent tried is some kind of PAE command that i can run from CMD, but on reading it appears to be only for 32 bit systems and so wouldnt help me, and although i could see mention of it, the actual command itself wasnt written, anywhere, and i cant find it, so cant try it.

 

 

Would anyone be able to offer any advice on what i could do next in an attempt to free up the RAM, as im out of ideas, and the guys over on tomshardware seem as stumped as i do, so the next logical step was for me to post on the manufacturers forum.

 

Many thanks in advance, Dan.

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Paul_Tikkanen
Posts: 42,904
Member Since: ‎07-13-2010
Message 2 of 2 (210 Views)

Re: DC5100 SFF and RAM...

Hi, Dan:

 

That is an odd situation you have there.

 

First of all you are aware that your PC even though it is running a 64 bit operating system, Windows will not "see and use" all 4 GB of memory, correct?

 

In order for Windows to "see and use" all 4 GB of memory when running a 64 bit operating system, an Intel based PC needs to have the Intel 965 or newer chipset.

 

Yours has the Intel 915. So that explains why you will never, ever see 4 GB out of 4 GB.

 

Why the memory is switching from one amount to another is beyond me. 

 

Most system memory goes into reserve for the onboard or add on graphics card.

 

I looked at the setup guide and there are no discrete video memory aperture settings to change like there is on the d530.

 

You can't update the BIOS unless you can do so via the DOS based flash method now that you have installed Windows 7.

 

That is the best info I can provide. 

 

I don't have an answer for the memory fluctuations.

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