HP ProDesk 400 G4 SFF PCIe Issue with Memory

[swishnets]

I am having a strange issue with my HP ProDesk 400 G4 when I install a PCIe card into either PCIe slot, the memory is cut in half.  The system currently has 2 8gb dimms installed so without a PCIe card installed, the system has all 16gb and with a PCIe card it only has 8gb.  I have gone through the BIOS to see if there was possibly a setting that could cause this and have been unable to find anything, I also did a BIOS reset and still the system will only show 8gb available when a PCIe card is installed.  Any help to solve this would be appreciated.

[itsmyname]

@swishnets -- some graphic adapter cards do NOT have any RAM on the card. What then happened is that your card has "borrowed" 8GB of your RAM, to use for video-processing, leaving only 8 GB for Windows to use.

Exactly which card do you have? You may need to purchase a different card that has its own RAM. Note that such "onboard" RAM usually is faster than the RAM on your motherboard, which is a "bonus" to you.

[swishnets]

Well actually I'm trying to install a 4 port Intel Nic.

[itsmyname]

@swishnets -- open the Windows "Task Manager".  Click to the "Performance" tab.

How much RAM is showing as "used" ?

Are there any device-drivers for the NIC that you have downloaded & installed, or did the NIC come with a CD-ROM that contains some older (?) device-drivers?

[swishnets]

Yes, I have the drivers from Intel.  As far as the amount of memory that Windows shows I will need to install Windows on it to see if it is able to see all 16 gigs.  I know the bios only sees 8 of the 16 gigs when the nic is installed.

[itsmyname]

@swishnets -- I will need to install Windows on it to see if it is able to see all 16 gigs.  

As the image shows, open the Windows "Task Manager", and switch to the "Performance" tab, to see the RAM that is visible to Windows.

[swishnets]

I installed Windows last night and all it is showing is 8gb, just like the bios when the additional NIC is installed.  When I remove the NIC all 16 gigs are available.

[itsmyname]

@swishnets -- so, we're back to your initial posting:

I am having a strange issue with my HP ProDesk 400 G4 when I install a PCIe card into either PCIe slot, the memory is cut in half.  

Does this happen if you install a different card ?

What happens if you start with 24 GB of RAM?  Still reduced TO 8 GB, or is it reduced BY 8 GB?

[CStingray78]

I am running into the very same issue with a 400 G4 SFF.  I've tried with matching modules from 4GB to 16GB each.  When I install my four port Broadcom based PCI Express NIC, the system no longer detects the RAM installed in the second slot (DIMM3).  I have even installed the PCI Express card in the x16 slot with the same result.  The RAM installed in the second slot is no longer detected.  I updated the BIOS to 02.38 Rev.A as well as reset it to defaults with the same results.  Any help is appreciated.