Question 16GB Ram, 8.1GB Hardware Reserved, tried every fix, looking for any hope

Jan 24, 2021
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Hi there,

This is a current part list for a build I'm working on upgrading: https://pcpartpicker.com/list/QcmcVc . It currently uses an up-to-date 64 bit version of Windows 10 since there have been a few updates over the years.

This build has worked for many years with an i5-4690, but I recently picked up an i7-5775c because it was low-cost and I thought it would be a cool upgrade which could give some tangible improvements. I carefully replaced the CPU and it seemed that all was well, I started benchmarking with the new CPU, however I soon noticed that I only had 7.9GB of usable RAM:

<Can't post picture for some reason>

However, Windows recognized my full 16GB of RAM, I just had 8.1GB of RAM "Hardware reserved". So, I started down the depth-first search of every google result I could find for similar issues. This issue did not occur in the past, however the exact time when it started may have been a few days ago when I upgraded the bios, but more likely it started when I actually replaced the CPU.

Screenshot of Resource Monitor:
<Can't post picture for some reason>
Screenshot of msconfig System Information:
<Can't post picture for some reason>

I can provide more data if needed, let me know.

Things I have tried:
  • I have the latest bios, I flashed it for compatibility with the new CPU
  • I reset the BIOS to the default.
  • I tried one-by-one enabling any BIOS setting that seemed like it might be related to memory. Particularly, I have the default display method set to PCI (not integrated graphics) and have the IGD multi-monitor feature off. The first and best theory that I have is that the memory is being reserved by the integrated graphics somehow, but these are the only BIOS options related to integrated graphics that I can find and they are electing not to use them.
  • I tried disabling the Windows pagefile
  • I tried un-setting the "max memory" checkbox in msconfig, however it was not checked in the first place.
  • I tried every permutation of RAM stick ordering that I could, putting each stick in each slot and trying to boot, but the issue persists.
  • I loosened the CPU cooler to relieve pressure from the board
I have also tried two of the four RAM sticks as individual pairs. When I any run any two of the RAM sticks, the issue does not occur; I get 8GB of RAM usable. This holds true for either of the two dual-channel slot pairs (2&4, 1&3). So, I have tried each combination of sticks individually in both slots 2 and 4 and 1 and 3 and they are fully functional, giving me 8GB of usable RAM in Windows. This, I assume, rules out a faulty RAM stick or a faulty slot. The only time that this issue occurs is when all 4 RAM sticks are in the board.

Moreover, many of the conclusions I have found for this issue point to it being a BIOS problem, but I can't think of any setting I can set in the bios that might fix it. Perhaps someone on this forum might know; maybe the RAM modules that I have are very slightly different somehow and I need to synchronize them when all 4 are in the board? I don't know.


Does anyone have any ideas? Thanks for the help in advance.
 
Last edited:
Jan 24, 2021
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hi, half ram hardware reserved means that half of your ram simply doesnt work
u can try reduce ram frequency, loosen up ram timings, increase ram voltage, increase proc ODT or CAD resistence (if available), overclocking bclk
It seems strange that half of the RAM doesn't work when it worked for several years prior to this, and any two of the RAM sticks are working individually in either of the two dual-channel slots (1,3 and 2,4). The only time the problem occurs is when all 4 of the RAM sticks are installed. Can you elaborate more on what you mean by they "don't work"?
For the overclocking, which of those things should I try first? Do you think those will have a chance to solve the problem?
 

alex_mormen

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Dec 2, 2009
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Oh wow. I have almost the exact same problem. Had a i5-4690 with 16 GB working before upgrading to a i7-5775c. 16 GB of RAM on 4 sticks. Working before. MSI Z97 board. I tried upgrading the BIOS as well. No resolution. 8.1 GB hardware reserved. Not sure what the problem or solution is. Tried reseating, resetting to default settings in BIOS, messing with maximum memory setting in Windows, switching XMP profile on and off. Messing with integrated graphics memory allocation in BIOS...
 

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