Hardware Reserved Memory 5.5GB

I have a windows 10 computer that i did a clean install during the free upgrade. Now i went the Task Manager to see that , my hardware reserved memory is 5.5GB. I have a 8GB ram and i can only use 2.5 gb.. How can i fix this?

Are you running the 32bit or 64bit Windows? With the 32bit you have approximately 3.571gb roughly to work with out of the first 4gb of memory installed. The rest is simply mapped out to hardwares. The 64bit on the other hand will handle upwards of 128gb of memory in theory.

Running the 64bit 10 Pro here with 16gb installed I see 2.9gb in use at the moment due to having browser windows and a few other startups running while idle it sits at about 1.5gb. The "Hardware Reserved" immediately implies the 32bit Windows where I wouldn't be seeing the 13.1gb available out of the 16gb total here.

If you had a few VMs one test would opening each one up with a player that allows multiple instances like VBox and wait until you see the "out of resources" type error when having a few using 2gb running! That would show if the TM was off! Ran into that when 7 was still early on with 4gb of memory and the old XP Mode plus a couple of other VMs running and tasked the memory!

Since you are running the 64bit the next step is to see if either the System File Checker tool can be a help or you may have to plan a clean install to replace the clean install as a last resort if not able to get this fixed in the present install. Generally the upgrades can turn out buggy while this can also be seen with clean installs at times just nowhere near as common place however!

To get the SFC going simply right click on the Start button and choose the Command prompt(admin) option preferred. Once that is opened up type in "sfc /scannow" and hit the enter/return key to start that up. If the tool finds any system files missing if not buggy it will or should replace them automatically. In previous versions if needed you would be prompted for the installation media used to install Windows with since certain files would have to be unpacked all over again.

The unfortunate side of that would be if the SFC itself is having a problem of it's own since you should be seeing well over 6gb available when the system sits idle. The TM is showing only 1.1gb in use which can vary a few hundred mb but over 5gb shows there's a problem!

When in doubt the rule of thought at times is to "Toss It Out"! I have to suspect you ended up with one of the more rare "buggy" clean installs compared to how many are still with their first upgrades running into problems. How old is the present install at this time? Tracing your steps backward from when this was first seen to the time of the clean install might indicate what made a drastic change if some 3rd party element is responsible?!

The Asus support site wasn't much help in finding out much about the memory other then listing the speeds of DDR3 it will take with nothing about the voltage whether 1.5v or 1.9v. You would think Corsair seen in your system specs would be among the brands in the QVC page list but I was unable to get onto that page from the board page for some reason.

If you are not mixing memory but only have the pair of dimms one potential issue is an incompatibility of some type between the memory you have installed now and the board itself. The Asus support page shows that model board will suppport upto 64gb so you are not running with oversized dimms one reason this problem comes up.