Windows 10: Installed memory: 8GB (6GB usable) - 2 GB is Hardware Reserved

BIOS is detecting all the DIMMs:
Code: [Memory Array Mapped Address] (Type 19) 13 0F 1B 00 00 00 00 00 FF FF 7F 00 16 00 01 20 ............... 00 00 .. Type 0x13 (19) Length 0x0F (15) Handle 0x001B (27) Starting Address 0x00000000 Ending Address 0x007FFFFF - 8388607KB, 8192MB, 8.00GB Memory Array Handle 0x0016 (22) Partition Width 0x01 (1)[/quote] However, only 6GB are marked as available for use:

Code: Range Address Length Type 0 0000000000000000 000000000009DC00 1:Available 1 00000000000F0000 0000000000010000 2:Reserved 2 00000000FEC00000 0000000001400000 2:Reserved 3 00000000F0000000 0000000004000000 2:Reserved 4 000000000009F800 0000000000000800 2:Reserved 5 00000000DFEF0000 0000000000010000 2:Reserved 6 0000000000100000 00000000DFDE0000 1:Available 7 00000000DFEE1000 000000000000F000 3:ACPI Reclaim 8 00000000DFEE0000 0000000000001000 4:ACPI NVS 9 0000000100000000 00000000A0000000 1:Available[/quote] Unfortunately I can't determine why BIOS is not giving the full size. Maybe it is failing to initialize one of the DIMMs but there's no errors logged that I can see.

Did you try using only one DIMM and testing each slot individually?

 

However, only 6GB are marked as available for use:

Code: Range Address Length Type 0 0000000000000000 000000000009DC00 1:Available 1 00000000000F0000 0000000000010000 2:Reserved 2 00000000FEC00000 0000000001400000 2:Reserved 3 00000000F0000000 0000000004000000 2:Reserved 4 000000000009F800 0000000000000800 2:Reserved 5 00000000DFEF0000 0000000000010000 2:Reserved 6 0000000000100000 00000000DFDE0000 1:Available 7 00000000DFEE1000 000000000000F000 3:ACPI Reclaim 8 00000000DFEE0000 0000000000001000 4:ACPI NVS 9 0000000100000000 00000000A0000000 1:Available[/quote] Unfortunately I can't determine why BIOS is not giving the full size. Maybe it is failing to initialize one of the DIMMs but there's no errors logged that I can see.

Did you try using only one DIMM and testing each slot individually?[/quote] When I use one DIMM in DDR3_1 or DDR3_3, the computer won't even boot up.
When I use one DIMM in DDR3_2 or DDR3_4, the computer boots up.

 

Did some search about your mobo and memory not recognized.. if hardware is fine, a lot of users reports, that checking CPU's pins showed one or more pins were bend.

Did you move your CPU lately? Pressing against it while installing memory?. Check its pins.

 

Yes, I removed the CPU but that was after I started experiencing the issue to see if I had any bent pins. I didn't see any bent pins. I took come pics... Dropbox - CPU

 

Forgot, you already checked all main possibilities.

 

Is this normal or does it indicate bad memory slots?

 

Hi,
You'd have to refer to the mother board manual
Some will only allow 2 designed slots to be used.

 

I'm not very savvy so I've attached the page from the manual discussing this. Can't tell if it would only allow two slots.

 

This configuration just indicates slot to be used, if running dual or 3 channel. Single stick run as single. At the bottom it's saying one stick goes into 1st slot.

Motherboard could be a problem. Load optimized defaults again, or even reflash the latest BIOS. Check CPU again (I know you did) - some of CPU's pins are controlling the memory.

Edit: take care, that slot 3 and 4 are populated with same memory sticks. You said you bought same type, but they are different. No chance you're gonna get the same chips after 4 or 5 years.

 

Thanks, I've tried both fail-safe and optimized defaults for the BIOS. I've also re-flashed the latest BIOS which I was already on. I even flashed to a newer beta BIOS that was available but it didn't help so went back to the latest stable release. Will check the CPU pins again.

 

Think you've done everything there is to be done. Check about same sticks again (in slot DDR_3 and DDR_4).


One more thing to check: in Advanced Chipset Configuration check UMA Frame Buffer Size. If there is something like that.. This is memory for integrated graphic. Don't know if your CPU has it at all..

 

I looked high and low and found nothing in the BIOS for Advance Chipset Configuration. Even so, when I had 4GB of memory, it was all usable, nothing reserved for hardware/GPU.