4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

Bit Baby

4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

I have 4x2Gb DIMMs newly installed in my Dell Precision T1500, but the BIOS (and OS, Linux 64-bit) are only reporting 4Gb.


DIMMs are all identical:



They all work individually.


BIOS (v1.0.1) reports them as DDR3 SDRAM Dual Channel, 133x10


The only way to get 4Gb is 2x2Gb in DIMM1 and DIMM3 slots (blue and black), which doesn't make much sense to me. Any other configuration is either ignored or won't boot.


Any suggestions?

6 Replies
Community Manager

Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

@johnlevon Thanks for contacting us today. I am sorry to hear you've been experiencing issues with the Dell Precision T1500.  It looks like the issue may be caused because of the system requiring a BIOS update. I would suggest checking Dell's site for the latest BIOS. Please let me know if this resolves the issue for you or not. 



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Bit Baby

Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

Well, I finally got around to upgrading the BIOS to Dell's latest (2.4.0), and it made no difference. No combination I can find will get the BIOS to see any more than 4Gb.


Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

I would blow compressed air across the memory slots in case they have some dust or dirt in them.  Examine the slots and pins  within the slot for any contaminants.   Make sure the DIMMs fully snap into place.


I would also unplug the computer and remove the CMOS battery for a while in case the BIOS settings have become corrupt.    Then I would reinstall the CMOS battery, enter the BIOS and load the defaults & reconfigure the date & time....Save & Exit then reboot again to check on the memory.   If the date & time are still correct, then you need to wait longer before reinstalling the CMOS battery.


I would then take one stick and try it in each of the slots.   I don't know if it will be recognized properly when installing out of order, but it is worth a try to determine if each slot is functional on their own. 


If you still have your original memory, reinstall it to see if it still works properly.  If it does, then keep it & try installing the new memory in the remaing slots.


Some people have mentioned removing the CPU and checking it for bent pins.   Some have had success just reseating the CPU.   Be very careful doing this if you've never done it before.   Sometimes the heatsink will pull the CPU out of the socket.   Sometimes running the computer first to heat the CPU may soften the heatsink compound and make it easier to remove the heatsink.   If you don't have any new thermal compound to use, then make sure to put the fan/heatsink back on in the same orientation.   (When the heatsink is removed, some of the thermal compound will stick to the heatsink & some will stick to the CPU.  If you don't refresh the compound, then you want to match it so the bare areas on the CPU match the area on the heatsink where the compound stuck.)   Also hold the CPU by the edges.   The CPU is keyed to only fit one way, so make sure it is oriented correctly or you will damage the pins.  Look at some videos as a guide.


Double check the labels on each stick and make sure they all match.  


Does the computer show any errors during POST or any error LEDs with all the memory installed?


If nothing works, it appears you may have a defective motherboard (or possibly CPU).





Bit Baby

Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb

I know this is an old machine now, but I would appreciate some help.


I have exact same problem as OP. The PC was stripped down, defluffed, cleaned and new GPU installed and the CPU heatsink removed, air blasted, cleaned and new Silver paste added. I reinstalled the memory cards (4 x 2 G identical boards) but the board slot numbers do not match the manual numbering. Reading from the CPU the Mboard marks them up as:

Dimm 3 blue

Dimm 1, black

Dimm 4, blue

Dimm 2, black

But the manual shows them as:

Dimm 1 blue

Dimm 2, black

Dimm 3, blue

Dimm 4, black


Just as the OP stated

All the cards read / work fine on their own

but I can only get 4G if I use dimm 1 + 3 (Manual numbering) which is the two blue slots.

No other combination works. Adding the remaining boards to dimm 2+4 does nothing. 

Bios 2.2 reports there is 4G and the pc is using a single memory slot. There is no means of enabling a second chanel in the bios.


Downloading Dell bios update 2.4 , reports succesful update when run, but the bios doesnt actually update. (PC running win10)

The PC did show 8G running prior to strip down and clean.

Tried every suggestion above a number of times but no success. Would appreciate some help!

Bit Baby

Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb


The memory cards only work and show 4G when plugged into dimm 1 blue +dimm 2 black (Numbered as in the manual)

which is unusual Smiley Embarassed)


Re: 4x2Gb RAM in Dell Precision T1500, only seeing 4Gb



You should remove the new GPU to make sure it is not introducing any problems.


You should try running the Dell Diagnostics to see if anything shows up.  Access it by pressing F12 for the boot menu.  Try it even when the memory isn't seen by the BIOS to see if the diagnostic throws an error.


You may want to inspect  the motherboard & use compressed air on it in case something very small fell on it during your maintenance especially around the outside of the memory slots since you have already blown air on the slots.  Check to make sure any jumpers are still present and all cables are properly seated.   Did you reconnect all the power supply cables to the motherboard?   You may want to disconnect any unneccessary internal & external devices as well.  Maybe even remove the motherboard in case something got beneath it or between it and the tray.   Double check the pins on the CPU as bent pins can be difficult to see and make sure they are clean.   Would any dust have gotten into the CPU socket?


It is a bit risky updating the BIOS while the system is behaving this way.  I believe you should have an option to create a bootable USB  drive for the firmware update or it may be possible to load the firmware from the USB drive while in the BIOS.   If not, I used to create a bootable USB drive using FreeDOS and copying the firmware updater to it.  


I would take one memory module and try it by itself in each of the slots to make sure they are all functional.   Check the memory to see if it is all identical (brands, speed, etc).  You should install identical pairs in the same color slots to minimize compatibility issues.  Don't be afraid to try three modules preferably in the correct order (slots nearest CPU).