Windows/BIOS doesn't recognize added memory

[brainrequired]

I decided to upgrade my laptop memory. I took 2gb ram out of my old thinkpad t400 and added in my laptop. Laptops original ram was 4gb PC3-12800. I added 2gb PC3-8500F stick. CPU-Z recognizes both channels and displays total of 6gb, while windows and bios only recognize 4gb. I'm running windows 10 64 bit. NOTE: original ram runs at 1.35v while the ram I added runs at 1.5v. Can that be an issue? My laptops BIOS is very restricted (It only shows total memory) so I can't change voltage. Should I give up and buy new ram? Thanks.

 

[Chicano]

If I read you correctly, your Thinkpad had 2 stick of 2GB ram (4GB total), you removed one 2GB stick and added a 4GB stick for a total of 6GB? (and it only recognizes 4GB.)


Check these Thinkpad T400 memory specifications from Lenovo.
https://support.lenovo.com/mx/en/solutions/pd005598

PC3-8500 Non-Parity (NP) Double Data Rate Three (DDR3) Technology
Two SO-DIMM Slots
The use of 1067 MHz SO DIMM memory is recommended for this system.
512 MB, 1 GB, 2GB, or 4GB memory
Supports up to 4GB maximum memory
Note: Only 64-bit operating systems support more than 3GB of system memory (RAM).

So there's your answer; the ThinkPad R400, T400 only supports up to 4GB of RAM... so it was not made to support more than that. You installed the 4GB total in one slot, and it may be recognizing 2GB out of it, you can test the laptop with that 4GB stick alone, and see if it recognizes 2 out of it or the full 4GB.

4GB is be the total RAM a 64 bit Windows will recognize... a 32 bit would recognize only 3GB. The BIOS and CPU-Z only point out that the total installed RAM size is 6GB not that all of it should work.

 

[brainrequired]

If I read you correctly, your Thinkpad had 2 stick of 2GB ram (4GB total), you removed one 2GB stick and added a 4GB stick for a total of 6GB? (and it only recognizes 4GB.)


Check these Thinkpad T400 memory specifications from Lenovo.
https://support.lenovo.com/mx/en/solutions/pd005598

PC3-8500 Non-Parity (NP) Double Data Rate Three (DDR3) Technology
Two SO-DIMM Slots
The use of 1067 MHz SO DIMM memory is recommended for this system.
512 MB, 1 GB, 2GB, or 4GB memory
Supports up to 4GB maximum memory
Note: Only 64-bit operating systems support more than 3GB of system memory (RAM).

So there's your answer; the ThinkPad R400, T400 only supports up to 4GB of RAM... so it was not made to support more than that. You installed the 4GB total in one slot, and it may be recognizing 2GB out of it, you can test the laptop with that 4GB stick alone, and see if it recognizes 2 out of it or the full 4GB.

4GB is be the total RAM a 64 bit Windows will recognize... a 32 bit would recognize only 3GB. The BIOS and CPU-Z only point out that the total installed RAM size is 6GB not that all of it should work.

My bad. My laptop is HP G5 250. I took ram from thinkpad and added in HP

 

[Chicano]

The HP 250 G5 Notebook specifications say it includes one 4GB RAM memory module (4 GB DDR3L-1600 SDRAM (1 x 4 GB)) so it should support twice that.

1. Have you tried the 4GB stick in both slots with the 2GB stick removed?
2. does it recognize the 4GB in each slot? if it does, it should support the 6GB of RAM.


HP 250 G5 Notebook PC (ENERGY STAR)
http://www8.hp.com/us/en/products/laptops/product-detail.html?oid=11489467#!tab=specs


This HP 250 G5 specificiations page in spanish says maximum supported RAM is 16GB.
http://www8.hp.com/mx/es/products/laptops/product-detail.html?oid=10180321#!tab=specs