Physical memory and available memory

Hi

My first post.I have added new memory, or rather second hand memory, to my Dell Precision 490, Windows Pro 7 64 bit system. (I bought an upgrade from XP Pro 32 bit) I have also upgraded the BIOS.

The new memory is two 4 GB sticks of FB ECC. In Setup the memory is displayed as two 2 GB sticks. I took out all the memory and just re-inserted the two 4 GB sticks. The system on re-boot reported no memory. I am thinking that my purchase is faulty, but then why would it be reported as two off 2 GB sticks when installed with the other memory if it was faulty?

I have download PC wizard 2010 and it reports Physical Memory as being 13312 MB which is what I should expect 13 GB. (2 off 2 GB, 2 0ff 4 GB and 2 off 512 MB). Task Manager reports Physical memory as 5117 MB ie it doesn't recognize the two 4 GB sticks.

Control Panel under System reports Installed memory as 9 GB (5 GB usable) recording the two 4 GB sticks as being 2 GB sticks! I don't understand why only 5 GB is usable and don't understand whether the memory I have bought is defective or not, or whether Windows is misreporting how much memory I have installed. Does anyone know what is happening?

Enable memory remap in your BIOS if it is available

@ logic earth

Thanks! On entering Setup I get Installed memory 5.00 GB memory speed as 533 MHz. Memory channel mode Dual. Memory techology: FB-DIMM DDR2 SDRAM (ECC).

The 490 can accommodate 32 GB: 8 x 4 GB.

Geoff

Well, if you are sure that the 4GB memory is not faulty, then make sure you insert them into right slots - dual channel memory should be inserted in proper order to work, consult your PCs manual on that. On my Dell Inspiron, the right order is 1 and 3, then 2 and 4 (there are only 4 memory slots).

@unifex

Thanks, I do not know whether the 4 GB memory is defective. It is is not recognized when inserted on its own. Whether that means it is defective is awaiting someone on this forum who has the knowledge to evaluate what is happening.

The Dell 490 has eight dimm slots arranged in a single row split into two "banks" 1-4 cream retainer clips 5-8 black clips. I have inserted two 2GB sticks in slots one and two and two 4 GB sticks in slots 3 and 4. The two 512 sticks are inserted in slots 5 and 6. There is no guidance in the Dell 490 manual other than putting them in pairs - banks do not exist. The system can accommodate a maximum of 32 GB 8 x 4 GB.

ggeoff, here you will find the memory-related chapter from Dell's instruction manual for Precision 490 - I guess that's your model. When inserting memory you should follow the directions precisely, especially pay attention to the slot numbers. Please let us know how this went.

Now, to check whether your system recognizes your new DIMMs, simply remove all other memory and put one new DIMM in slot 1. If the BIOS won't see it - and the computer won't boot - that means that either the DIMM is defective, or it is not suitable for your motherboard, or you may need a BIOS upgrade. I don't see any other possibility.

Another thing to consider is also checking whether or not that is the correct memory for your system. When you got the second hand ram, did you go through the memory configurators for Crucial, or Kingston or the like to make sure it works for that model of computer.

I have to ask this cause sometimes people think they have the right kind of ram, but ended up getting the wrong kind, not knowing that the speeds and chips make a difference.

Hi

I have twice tried to reply to posts and have been told that I am not logged on. so maybe third time lucky

Geoff

Yes seems to have worked. The supplier has reassured me that the memory supplied is correct.