Installed RAM 16GB, only 4GB in BIOS - Precision T5400

I have a T7400 same vintage as your T5400 also with 8 x 2GB RAM 2 x XEON E5405 processors, and Windows 7 x64.  I am however at A05 BIOS.  I remember no BIOS settings for memory size.  I kind of doubt that your PC came with 16 GB of RAM more likely more likely 4 GB and memory upgrader were done over time, so I ask this question, when you say the memory is identical, are you including voltage, and timing values.  Is the memory generic or specifically design to Dell specs?    

I had a bad experience upgrading a Dell PE T410, where two DIMM had different voltage requirements and therefore was not seen.

Thanks msgale for your response.

Regarding your question about identical memory - all 8 sticks are from same vendor, same brand, and report similar reading on CPUID. And yes, they are generic but supposed to work with T5400 (FBDIMMS).

Would BIOS report all 8 slots occupied with 2GB ram but installed ram = 4GB if the motherboard was bad? I would think it would fail to report all 8 sticks.

I feel there is some setting or tweak that I am missing here.

Hope to find some more ideas.

Update:

Got new set of memory sticks from a different vendor. This time I got 4 sticks of 2GB FBDIMM each (identical in make and value). Installed them on slots 1 through 4 (all white slots). The BIOS recognizes the 2GB sticks in each of the slots, but the installed memory is reported as 2GB. On Windows properties - Installed memory shows as 8GB (4GB usable). Please help!

Thanks,

Have you ever tryed to put them in the advised oder:

one in the first white bank

one in the second white bank

one in the fist black bank 

one in the second black bank.

You should never use Ram memory only in one colour at a time if you use pairs

greeting DS

I may have some experience here to help with this issue.  What would be first need to do is understand that only the Intel 5000x chipset supported quad-channel up to 32gb 4gb x 8.  The Intel 5400X chipset apparently supports only 32gb with risers.  The risers install in slot #1, and slot #2, with slot 3,4 empty.  The risers would contain 2GB X 8 for the Intel 5400X t5400 spec to 32GB.

Wipe the OS drive and install a fresh copy of windows 7 professional or ultimate of the latest build or Windows Server 2012.  This will allow the "Server" to talk some business on Windows Server.  With all 32GB completely usable to the OS at lightning fast quad-channel speeds.

Otherwise you can pull quad-channel 16GB without the risers.  Just simply install (2) X5470 3.33Ghz 1333Mhz FSB Quad's, then BSEL the X5470's from 3.33Ghz to 4.00Ghz per Quad.  It requires a piece of electrical tape covering one pin when installed in the socket.  The 2GB x 8 = 16GB of PC2-6400 DDR2-800 ECC all exactly the same model numbers and build dates.  This will allow the Intel 5400X chipset to reach pinnacle levels of performance at 1600mhz fsb on the X5470's.  So you'll have 32Ghz Of Pure Processing Power. 

I'm building a Precision T5400 custom built server in a Chenbro with this configuration dual 4ghz x5470s, 16gb ddr2-800, dual Titan Z's, all running on the N1000P-00 1,080W Precision 690 power supply.

GOOD LUCK!

Sounds like I've almost the same problem: T5400, BIOS A03, had installed 8x 1GB, showed up 8GB.

I've removed all sticks and replaced them with 8x 2GB (FB-DIMM, ECC, 667MHz).

In the Memory section of BIOS, all sticks are listed correctly, but total memory shows 8GB.

Then I flashed a new BIOS, now it's version A11, but without any effect. The computer works using only 8 GB, though 16 GB are installed.

BTW I'm running Linux (Mint, similar to Ubuntu), but IMO the OS has nothing to do with it. It's the BIOS which doesn't detect all memory.

Can anybody confirm that clearing CMOS could help in this case? Other suggestions?

You are probably running a 32 bit OS.  The maximum addressable memory for a 32 bit OS is 4GB.  For addressing all of the memory, you need to install a 64 bit OS.

No, running 64-Bit Linux. And it works with 8 GB. BIOS shows 8x2 GB, but total memory is showing up as 8GB.

It is very sad to have Rev 11 of a BIOS which has the same bugs as Rev 3. And I'm not the only one having this kind of problem.

Same problem but with a similar T7400

even after upgrading fresh to windows 7 64bit it still shows 8GB - but only 4 usable! (8x1gb)

its clear its a motherboard bug, please fix it! 

Hi all!

It looks I'm having the same issue here.

I tried all possible memory configurations and in MOST CASES bios fails to detect half of the memory.

BUT SOMETIMES it detects all memory if on boot prompt strike F1,  unfortunately as soon as you go to BIOS it either crashes or decreasing memory to half

As I can see it's about 2 years since question was raised. If anybody from DELL found a time to sort it out or if anybody managed to find the solution?

thanks

Firstly have you installed the correct configuration of memory?

http://downloads.dell.com/Manuals/all-products/esuprt_desktop/esuprt_dell_precision_workstation/precision-t5400_user%27s%20guide_en-us.pdf

Follow page 187 - 188 - compare the specifications written on the memory Vs whats given in the manual. 

Also 32 bit OS addresses only 4 GB of RAM, show 3.25 GB in Windows 4 GB in BIOS. 

I believe it's a motherboard issue. I have 2 T5400's. One is working great with 32gb of ram 8x4gb running on Win7 64 bit. 

The other is also Win7 64 bit. I had a problem with some 1gb memory in slots in 7 & 8. I took out the RAM leaving the machine with 6gb. I recently bought 16gb (8x2gb) to upgrade that machine. 

I loaded it up with 16gb, started it up and started getting a beeping from the Motherboard. Started troubleshooting. Narrowed it down to memory slot 7 & 8. It won't recoginize anything over 1gb of ram total. I had 2 old 512 sticks. I put those in. Came up fine. BIOS recognized it. Worked fine. Changed that out to 1gb sticks. Same MB beeping issue.

You might not have the beeping, but if each slot is only utilizing 512mb of RAM regardless of what the BIOS says is installed, then your max memory would be 4gb. You can get a replacement MB for relatively cheap. I suggest that route.

Hope this helps.  

I've seen some follow ups.

Whoever reads it please do not mind comments about incompatible memory or 32/64 bit systems.

Just follow my procedure and it will help

So far I'm happily using all of 16GB

My 2 cents,

I've refurbed at least 100 x T5400/T7400 to date. FB RAM is cheap so upgrading to 16/32GB is affordable & easy.

Bear in mind that the machines probably had much less at new and, crucially, not all DIMM slots filled...

My point is that DIMM slots get dirty.  MAKE SURE you give each slot a proper clean with appropriate solvent and air and inspect for debris.  I have had at least a dozen PCs baulk at initial RAM upgrade only to find after a thorough clean all works as expected. (Obviously make sure the RAM sticks are clean too!)

Also follow the recommended population routines ( stated a few posts above) if you are NOT filling every slot.

Hope that helps!

ATB