Acer Aspire 5552 (Athlon P320) upgrade to 8GB -> "4.3GB Hardware Reserved"

Hi,

I've been refreshing a friend's old Acer Aspire 5552 (Athlon X2 P320, HD4250), bios V2.01.
So far I've
- replaced the 500GB HDD with a 500GB SSD,
- done a fresh installed of Win 10 Home x64 (using the original Win7 Home Premium key)
- replaced the 2x2GB Single Rank PC3-10600, with 2x4GB Single Rank PC3-12800

The memory is detected fine (though as expected it only clocks at 540MHz), and checks out fine in a memtest64 test.

The problem is Windows is reporting 4.3GB of the memory is "Hardware Reserved" aka the bios is preventing the OS from utilizing it.
Acer's website did advertise this machine as supporting 8GB, but I guess at the time they never sold any SKU's with 8GB and so never discovered this bios bug?
As far as bios options go, it's pretty useless - only boot order is customizable.

Over the years this issue has been reported several times, such as this:
Memory Upgrade on Acer Aspire 5552 — Acer Community
However none have provided a concrete solution.

I'm guessing my only hope is that a later bios update has fixed the issue - however Acer's website provides no bios versions, nor any flashing tools. (it doesn't even recognize the laptop's serial# !)

Does anyone know where I can get reliable bios versions (and flashing tools) for legacy laptops such as this? Does Acer have a repository of some kind?
My Googling has picked up bios versions as high as V2.17 for this laptop series, but I'm hesitant to flash bios revisions with unknown compatibility as there are many configurations of the Acer Aspire 5552 series, with both Intel & AMD CPUs.

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TJJ

Just realized I had another laptop with 2x4GB dimms, gave them a try in the 5552 and they're recognized correctly and fully usable.

So looks like the problem is just a hardware incompatibility.

This is surprising, as the 5552's original memory was Samsung (2GB 1Rx8 PC3-10600S-09-10-ZZZ).

The memory that didn't work was also Samsung (4GB 1Rx8 PC3L-12800S-11-13-B4).
The memory that does work is SK hynix (4GB 1Rx8 PC3L-12800S-11-13-B4)

I'd assumed memory from the same manufacturer would've had a higher chance of working...
At least I don't need to go faffing around with bios updates

TJJ

Through further investigation (mixing and matching the various ram sticks) I think one of the 4GB Samsung dimms is faulty.

billsey

That makes more sense than the different manufacturers with the same specs acting differently. I'm a bit surprised that if the stock memory is DDR3 and the replacement is DDR3L that it works at all, since those two memory types run at different voltages. The chipset must be smart enough to see the difference and adjust to match. Just don't try mixing the two types...