[SOLVED] 16GB Memory installed. BIOS detects it, Windows 10 detects it, but half of it is "system reserved."

[Lt Mashumaro]

Title explains it all. I have a fresh installation of Windows 10 Home, and before I reinstalled Windows, everything was detected and working properly. Now for some reason, half of my RAM isn't detected. I've done extensive research on this matter and nothing I tried works. The RAM is all identical. I have 4x4GB of Patriot Viper 3 sticks. Although it is all identical, I bought them at different times so the serials are different on both sets of 2 sticks. To fix the issue, I have tried

• Reseating the RAM.
• Going into msconfig and making sure that the max memory is unchecked in the boot tab.
• Adjusting the paging options(?) as advised in this thread.
• Ensuring that the DIMMs are in corresponding slots.
• Turning on the XMP profile (It failed to POST after this step).

Nothing I have tried works. I installed Speccy so that someone a bit more knowledgeable than I might have some valuable input. Here's a link to my snapshot.

 

[Calvin7]

Use of multiple (2x4GB) kits does not make one (4x4GB) kit.

Multiple kits have no guarantee to be compatible together.

 

[Karadjgne]

You don't have 4x4Gb, you have 2x sets of 2x4Gb that are only identical on the outside heatshield and primary settings. On the inside, they are very different.

A ram stick I comprised of multiple ram chips, ic's, and these ic's are made from silicon. Silicon is not pure, it had impurities that differ in levels and composition from sheet to sheet. One sheet might have lead, another copper, another iron etc. These don't affect the Primary timings much, the 16-19-19-39 2T, but what you don't see is the 40+ Secondary and Tertiary timings. The impurities do affect those levels greatly.

Any kit you buy has compatible impurities, all the timings sync. Buy a second kit, it may or may not have compatible impurities, sometimes you can force sync by voltage changes in ram or cpu, sometimes nothing works.

So it matters not that the heatsink matches, the ram is different. You may need to manually adjust settings to get compliance, auto settings like XMP can amplify differences.

That could mean a small bump in Northbridge (cpu/NB or NB) voltages, system agent, even changing the sticks from 1.5v to 1.505v upto 1.55v. Or changing timings to 9-10-10-26 2T etc.

 

[Lt Mashumaro]

Use of multiple (2x4GB) kits does not make one (4x4GB) kit.

Multiple kits have no guarantee to be compatible together.

You must have missed the part where I mentioned that prior to the reinstallation of Windows 10, everything was detected and working properly.

 

[Lt Mashumaro]

Bumpity-bump-bump.

 

[Lt Mashumaro]

Okay, my problem is solved. For <Mod Edit> and giggles, I decided to just swap the 4 modules around. RAM sticks 1 and 2 were in lanes A and C, and RAM sticks 2 and 4 were in lanes B and D. I switched them around to where RAM 1 and 2 are now in B and D, and 3 and 4 are now in A and C. For some unknown reason that helped, and now I have all 16GB of my RAM usable.
PCs are weird, man.