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Savemejebu5
1 Nickel

Studio XPS 9100, reads only 1/3 of installed memory

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I began an upgrade of my factory installed 9gb RAM a day ago, with 24gb RAM, as part of a bigger system overhaul (incoming SSD  as well). To start this off, i ordered six matched triple-channel modules, each 4gb. That is, the 6x4gb g.Skill Ripjaws pack recommended in an old thread here, as these worked in their same system (and I knew the memory setup in this system was "odd" from other threads on the matter).

Anyways, after installation, the system could not post, and beeped twice: indicating no ram. I immediately began troubleshooting the chips (as best I can anyway when it seems I can only test them in triplicate). I cleared CMOS settings several times along the way, selecting default settings. At one point I got a five beep error code (bad CMOS chip) but it went away after a few minutes of leaving the machine off and reseating the chips. I finally narrowed it down to a possible failure in the pink DIMM slots (#4-6), or the chips in those slots. Further troubleshooting reveals that any chips in those slots failed to work (even three verified working ones). Looks like I'll need a new mobo soon

Sigh. Despite my care and twenty years experience with these kinds of upgrades, my handling of the upgrade must have killed a slot.

So i proceeded to start the system with 4gb RAM each in Slots #1-3, however bios now reports only 4gb. EDIT: added info. computer only works in triple Channel, and shows 1/3 of total Ram regardless of installed chips. Tested with memtest86 and it shows 1/3 of total Ram as well. to be clear no single Channel testing is possible because computer will not post with one chip or two. 

Observe the issue as well: How can I even have 4 gigs of RAM in a system that won't post unless it is in triple channel mode (3 chips)? Did I misunderstand something about the limits and requirements of the system? Shouldn't I have no less than 12gb showing up right now in CMOS, since three 4gb chips are installed? With original 9gb memory installed, it will not post. With 6gb of that original memory installed it shows only one third again (2gb). 

PS: guess I also need that new mobo sooner than I thought.. but still.. my curiosity and confusion remains and perhaps this is a clue to another issue of note

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Tesla1856
6 Gallium

Re: Studio XPS 9100 running with 4gb RAM?!

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@Savemejebu5 wrote:

 

1. Configs that Do post: original 6gb (3x2gb in slots 1/2/3), original 3 gb (3x1gb in slots 1/2/3), 

2. Based on this I've figured one of the slots (4/5/6) is bad.

 


1. Then I would fall-back to one of these. 6gb should get-you-by until you can get another machine.

2. Yes, looks like one of the slots (or supporting circuitry) in the Secondary (Tri-Channel) Memory Bank got damaged during the upgrade.

Remember, these machines are old. You really have to baby them and be very gentle physically. Damage from Static-electricity is real. Damage from non-dissipated flea-power is real.  

Sometimes the best "upgrade" to an old machine is to just leave it alone and let it run 100% properly and 100% stable. Anytime you get inside a computer, you are risking killing-it. Yes, technicians train to do this (and now you see why).


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19 Replies
Savemejebu5
1 Nickel

Re: Studio XPS 9100 running with 4gb RAM?!

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Since I know someone will ask..

I'm running BIOS version A04.

Windows 7 Home (SP1) reports 4GB as well. I don't have my bootable Linux on me or I'd use that to confirm.

Worth noting: All parts besides RAM are stock, except for an added (replacement) network interface card.

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Tesla1856
6 Gallium

Re: Studio XPS 9100 running with 4gb RAM?!

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Yes, looks like it's tri-channel memory.

https://www.dell.com/support/home/us/en/19/product-support/product/studio-xps-9100/manuals

Notice which set of 3 DIMM slots comprise the Primary Memory Bank. Machine should run with only those 3 DIMMs installed.

Install original memory and make sure you did not damage your motherboard. Once it POSTs and boots, an ePSA test or memtest86.com should confirm that.

 


Registered Microsoft Partner and Apple Developer
- Like many of you, I can appreciate a good game-engine.
- I answer questions here, but I'm not a Dell employee.
- Consider giving posts you like a "thumbs-up"
- Posting models-numbers and software versions speeds trouble-shooting.
- Click "Accept as Solution" button on any post that answers your question best.
Savemejebu5
1 Nickel

Re: Studio XPS 9100 running with 4gb RAM?!

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I confirmed that something is wrong with the slot before my OP by interchanging the DIMMs 

Just the same, I ran memtest. But now it gets weirder: No errors found! 

Any clues about how my 3x4gb install can pass memtest, yet  show only 4gb, not 12gb (expected)? System is 64 bit Win 7 Home which I know 32 bit is limited to 4 gig - but I'm checking in CMOS anyway. I ask because while i guess I'm returning the ram (since I need a mobo), I'm not reporting it defective either I suppose, since the chips all seem to work.. but just wut exactly is going on here, ya know?

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speedstep
6 Thallium

Re: Studio XPS 9100 running with 4gb RAM?!

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You chose HIGH Density cheap ram and its not ever going to work.

Must be LOW Density and Dual or Single rank.

Must NOT BE ECC or Registered or buffered or Quad rank .

http://www.crucial.com/usa/en/compatible-upgrade-for/Dell/studio-xps-9100

CT2793211

  • DDR3 PC3-12800 • 8-8-8-24 • Unbuffered • NON-ECC • DDR3-1600 • 1.5V • 512Meg x 64 •

 


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Tesla1856
6 Gallium

Re: Studio XPS 9100 running with 4gb RAM?!

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@Savemejebu5 wrote:

1. I confirmed that something is wrong with the slot before my OP by interchanging the DIMMs 

2. Just the same, I ran memtest. But now it gets weirder: No errors found! 

3. Any clues about how my 3x4gb install can pass memtest, yet  show only 4gb, not 12gb (expected)?

4. System is 64 bit Win 7 Home which I know is limited to 4 gig - but in CMOS too?


1 & 2. I've never seen a bad MB/slot/DIMM/etc. pass MemTest86.com . Are you sure you are reading it right?

3. No. But what you should be trying is 1gb-x3 or 2gb-x3 (your old DIMMs).

4. No, there is no such limit.


Registered Microsoft Partner and Apple Developer
- Like many of you, I can appreciate a good game-engine.
- I answer questions here, but I'm not a Dell employee.
- Consider giving posts you like a "thumbs-up"
- Posting models-numbers and software versions speeds trouble-shooting.
- Click "Accept as Solution" button on any post that answers your question best.
speedstep
6 Thallium

Re: Studio XPS 9100 running with 4gb RAM?!

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There is a Ram Limit for WIN7 Home but not WIN7 Pro.

maximum RAM limit for 32-bit Windows 7 editions is 4GB

Here are the upper RAM limits for the x64 editions of Windows 7:

    Starter: 8GB
    Home Basic: 8GB
    Home Premium: 16GB
    Professional: 192GB
    Enterprise: 192GB
    Ultimate: 192GB


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Savemejebu5
1 Nickel

Re: Studio XPS 9100 running with 4gb RAM?!

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@speedstep : I verified this Ram would work through the manufacturer of my computer, anecdotal evidence, and the manufacturer of the ram. It is compatible by all accounts except your own. But okay, this problem seems to go elsewhere anyway..

PS thanks for posting the limits. I was trying to communicate that i should not be limited to just 4gb

@Tesla1856 : tried the computer with many RAM configurations. Replaced the CMOS battery to be safe.

Configs that fail to post: aftermarket 24gb (obv). original 9gb (hm!). Any single or dual Channel configuration (I think this is as designed). So.. Any configuration involving all 6 slots fails now. Bad slot I think.

Configs that Do post: original 6gb (3x2gb in slots 1/2/3), original 3 gb (3x1gb in slots 1/2/3), new 12gb (3x4gb in slots 1/2/3). 

Based on this I've figured one of the slots (4/5/6) is bad.

What's strange about the configs that Do post is that BIOS always shows just one-third of the memory (2gb when there are 6gb installed, 4gb when there are 12 gb) and it passes memtest86 which also shows that same amount, so it's obviously not testing the other two thirds. Based on that I would say I have bad slots in 1/2/3 as well.

Maybe I missed something though.. 

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speedstep
6 Thallium

Re: Studio XPS 9100 running with 4gb RAM?!

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High density ram will show less than the amount installed.

That ram is not compatible.

Tri channel compatible ram works fine in all 6 slots when its the correct ram.

The linked model from crucial works fine in the XPS 9100 as well as the precision T3500 etc.

DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 512Meg x 64


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The forum is primarily user to user, with Dell employees moderating
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Savemejebu5
1 Nickel

Re: Studio XPS 9100 running with 4gb RAM?!

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@speedstep

Yes. However, since the computer is showing less than the installed RAM - even with the the original sticks- EDIT: and it will not post it in single Channel mode regardless of RAM, I can only conclude the issue lies elsewhere. 

EDIT: See reply to other user above

Also see first post and amended thread title which reflects the issue I now find needs diagnosing. 

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