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May 4th, 2015 07:00
Need some help - having problems with Dell Workstation BIOS not making all RAM usable
Hi,
I'm having problems upgrading the RAM in my T7400 workstation. I previously had 8 x 1 Gb modules and I'm now trying to use 8 x 2Gb (total 16 Gb). This fills up all 8 DIMM slots on the motherboard.
The replacement RAM is of the correct type, PC2-5300F DDR2, CL5, EEC Fully Buffered (same type as I had before). Each stick is also the same manufacturer (HP Micron), size, rank, timings etc. The problem is the BIOS won't recognise more than 8Gb as usable (it does detect all 8 sticks as it lists out all of the modules).
This is what I've tried so far:
- Tested each module independently in DIMM slot 1 and it's recognised fine. (And I know all of the slots work, since I previously had 8 x 1Gb working ok).
- I tried putting 8 Gb in DIMM slots 1-4, still only reporting 4 Gb usable (all modules detected).
- I ran memory tests, everything checked out fine.
- I reset the CMOS with the RTC jumper (suggested elsewhere on the forums).
- I could find no bios option to remap memory.
Windows 7 Pro also shows 16Gb installed but only 8Gb usable (this is not an OS issue, since the BIOS is showing the same problem, before it even gets to loading Windows).
I haven't tried flashing the BIOS but I doubt this is the issue. I've been through the changelog of each revision after mine and it doesn't mention anything about fixes to memory detection (Also similar reports of my issue said upgrading the BIOS made no difference). I'd rather not mess things up when everything else runs smoothly and I'm very much out of warranty.
Of course, Dell won't help directly without trying to bill me for technical support.
Can anyone please suggest anything else I can try?
Thanks for reading.
kirkd
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5.2K Posts
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May 4th, 2015 08:00
You seem to have done all the testing necessary. Others have had similar problems with NO posted solutions..What was the sourece of the Modules. Ifyou haven't done this, check on the Crucial web site to see what they recommend for the T7400. Also many RAM modules have similar specs, but not all correctly specd modules will run in Dell computers; they are very picky!!! For whatever reasons, Dell's won't run on just any RAM. Some other OEMs have similar problems. Best to look to Crucial or to the manufacturer of the modules originally in the T7400.
The only other thing I can suggest is to check the number of RAM RANKS in each module. Most computers will only handle a limited number of RANKS. RANK is loosly related to the number of individual chips needed to achieve the total RAM. I would suspect that the T7400 could handle most anything, however, as, with risers, you can load in an ungodly amount of RAM.
speedstep
11 Legend
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47K Posts
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May 4th, 2015 09:00
Dimms that show half of the ram are High Density 4 rank and not compatible. Any ole Joes crab shack ram doesn't work. Only Specific vendors ram works. Buying ram based on a cheap price almost guarantees that its high density. High density modules have less ram chips on them and are therefore cheaper.
DDR2 PC2-5300 • CL=5 • Fully Buffered • ECC • DDR2-667 • 1.8V • 1024Meg x 72 •
HIGH Density Ram WILL NOT WORK.
http://www.crucial.com/usa/en/precision-workstation-t7400/CT3531857
Franco G
4 Posts
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May 4th, 2015 10:00
Hi Speedstep,
The modules I have are dual-rank. They are these:
www.micron.com/.../71ee3eb5-8358-47d4-a889-e65d275477d6
(See penultimate bullet point on the "Features" tab).
Thanks.
RoHe
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May 4th, 2015 11:00
Does the diagnostic LED code (page 26) tell you anything?
Franco G
4 Posts
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May 4th, 2015 18:00
Thanks for the reply. The source of the modules was a memory reseller. The manufacturer (Micron) and memory type is listed as compatible for T7400 in several other places I've seen also.
The rank of the modules is 2 (dual), according to this BIOS screenshot I took and the official datasheet.
Franco G
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May 4th, 2015 19:00
Thank you for the link to the codes. On start-up I see nothing indicated of any use unfortunately. I also checked the BIOS event log which shows nothing either.