Laptop RAM upgrade failure

I replaced the two gig RAM in a Dell Latitude E-6400 and an HP 620 with eight gigs. On both laptops, System gives “8 Gig RAM, 2.8 usable”.
What’s wrong?

Using 32-bit Windows?

64 bit Windows 7, updated to Win 10.

Does it make a difference in what slot you stick the RAM?

Does memtest86 successfully test all 8 G ?

Did you put in a single 8GB stick? I ask because some laptops have more than one slot and you need to upgrade the memory in pairs. When I upgraded my laptop (Acer Aspire) I used 2 4GB sticks in the memory slots and it worked with no problem.

Have you done any BIOS updates on either laptop? It’s possible that you may need to update the BIOS so that the laptop properly utilizes the higher capacity chips that you installed.

Take another look at what blondebear suggested above, specifically the bold text.

Two four gig sticks.
I’m curious that both laptops recognize that 8 gig are present, but use just over two.

If it was a 32 bit issue, you would have been able to see 4 GB. 2.8 makes no sense.

What brand and specs for the RAM?

On my Windows XP machine with 4 GB only 2.5 GB was visible.

It can depend on your video card as they mapped their address space at the top end of RAM which reduced the available addressable space for the OS. A computer as old as a Latitude E6400 wouldn’t have had a discrete graphics card that used more than 1GB of RAM.

Dell’s specs, current on the web, say the laptop can take 16 gigs.
Well, they are both running Windows 10, the HP is rather slow, but the Dell ain’t bad.
Thanks, fellows.

You didn’t happen to buy on the RAM on eBay, did you? Could it be one of those hacked/fake/relabeled RAM modules?

As far as the Dell is concerned, you might want to check this out on their support forum:

https://www.dell.com/community/Latitude/E6400-8gb-RAM/td-p/7350978

Definitely check which BIOS version you’re running. The examples shown on the page are both running the A34 revision level.