Using 8 GB RAM, but BIOS and Windows say only 4080 MB/3.9 GB are usable! No answer for 3 months!

[Demuny]

Hey.
I've been tackling this problem for about 3 months now. My RAM is 8 GB (2x4) of Ripjaws X memory. I have a brother with an identical pc. Windows 8.1 64 bit and my BIOS recognize 8 GB of RAM, but are only allowing me to use 3.9 GB or 4080 MB. How do I fix this? I've tried everything:
I reseated the RAM, enabled remapping, updated BIOS, did something from a large post, something about changing the RAM speeds, I manually set the frequencies, voltage, etc. I RMAed the motherboard! I tried one stick at a time, they both work. I selected and deselected Maximum memory in Windows. I reseated every component!
Please help, I cannot take this. I have gotten no helpful answer for a long time.

 

[Demuny]

Let me get this straight...
1. You and your brother have identical PCs.
2. He has 96.1MB reserved and you have 4.1GB reserved memory.

What I suggest to do next is the following:
1. Set up the computers next to each other.
2. Enter into the BIOS in both computers.
3. Enter each screen in his BIOS, and whatever is shown there, copy it into your BIOS. If the hardware is identical, then you should have identical setup.

Make sure that every last BIOS setting is the same, just to eliminate a BIOS misconfiguration issue.

If this does not work, then there is most likely a hardware issue. I would ask if you bought your memory as an 8GB kit, or did you purchase two 4GB sticks? When you purchase 2 sticks separately, and not as a kit, then they are not guaranteed to work together, even if they are the same brand/model of memory. If you want to use more than one stick of memory, you need to buy them together as a kit.

1. Yes, the PCs are exactly the same.
2. Yes.

I will try that. I have not tried all of the BIOS settings, so I will look at that. The 2 sticks came in a 8 GB kit, so they should be compatible.

 

[Demuny]

What CPU? Not many can carry 4 sticks at 1866. Try at 1600, 9-9-9-24, 2N, 1.575 and CPU/NB voltage at 1.2. Can also try the sticks in slots 1-2, that will be single channel if all is seen or none is seen then it's a memory channel problem and quite possibly could be an overly tight CPU cooler on one side or in one corner,( loosen it up then snug down as evenly as possible, not real tight, tight) or might pull the CPU and check for bent/broken pins.....can try these, and let us know the CPU

I loosened the CPU cooler, no luck. I also checked for bent pins, and every pin is perfect.

 

[Tradesman1]

Have you tried at 1600?

 

[officialexpert]

Try with all new RAM Sticks if problem persist again you should replace your Motherboard.

 

[Demuny]

Have you tried at 1600?

Yes.

 

[Bad_Kitty13]

it could be the mem controller on your cpu too, have you ever tried your bros cpu in your setup?

 

[Demuny]

it could be the mem controller on your cpu too, have you ever tried your bros cpu in your setup?

No, but I'm afraid to because I don't want any of his components to break from my PC :l

 

[Demuny]

I noticed that when I checked CPU-Z, it says the RAM is in Single Channel mode, when they are set up for Dual Channel... What component would be the culprit for this?

 

[Beezy]

motherboard? i think, make sure in the manual what is says about dual channel config mode

 

[Beezy]

I THINK YOU HAVE TO RUN THEM AT 1333 MHZ TO ENABLE DUAL CHANNEL MODE

 

[Demuny]

I THINK YOU HAVE TO RUN THEM AT 1333 MHZ TO ENABLE DUAL CHANNEL MODE

No, because my brother with the same PC runs his RAM at 1600 MHz and CPU-Z says Dual Channel.

 

[Tradesman1]

Could be a weak MC on the CPU (very common), mobo itself, CPU cooler too tight on a corner or side, bent/broken pins

 

[Demuny]

Could be a weak MC on the CPU (very common), mobo itself, CPU cooler too tight on a corner or side, bent/broken pins

I got a new mobo from ASUS after RMAing it, so I dont think that would be the issue. I checked for bent and broken pins, everything was perfect. I also loosened the heatsink. Is there any way that I can find out if the MC is weak?

 

[Demuny]

Any solutions? I am sick of this.

 

[Tradesman1]

Can try swapping the CPUs or taking it to a shop

 

[T_T]

At this point, the things that have me curious are:

1. What happens if you put your RAM in your bro's comp?
2. Save the BIOS/UEFI config into a profile, then load defaults. Do this for both PCs. What are the results?
3. Do you have a different CPU, if you don't want to use your bro's?

 

[Demuny]

Guess what!
I finally put the sticks in slots 1 and 2, and all 8 GB were recognized! But... why can't I use them in dual channel mode??

 

[Tradesman1]

Have to be in different channels 1-3 or 2-4

 

[Demuny]

Have to be in different channels 1-3 or 2-4

When I put them in 1-3 or 2.4, only 3.9 GB is recognized...

 

[Xibyth]

You mention your brother is using windows 8, what about you? Otherwise, reset your bios and use the xmp profile to configure your memory.

 

[Demuny]

You mention your brother is using windows 8, what about you? Otherwise, reset your bios and use the xmp profile to configure your memory.

We both use Windows 8. We also both use the exact same BIOS settings.

 

[Xibyth]

You mention your brother is using windows 8, what about you? Otherwise, reset your bios and use the xmp profile to configure your memory.

We both use Windows 8. We also both use the exact same BIOS settings.

Did you try memtest. If you followed all the other suggestions it seems its just an intermittent error which still means the RAM is bad. Run it from a flash drive. Its easy enough to find. But you would be surprised how finicky RAM can be. Be sure to run the test more than a few times, since it seem they are shorting out. And actually now that I think of it try his RAM in you PC as well, that would ultimately rule out any motherboard configuration and it would definitely be one of your RAM sticks.

 

[911brutal]

Hi, im still noob at posting, but not on hardware..
just to add .. i use 2 4G Kingston 1600 that worked fine on dual ch. for almost 2 years and i decide just to put a better thermal paste on the CPU ( touched nothing else xcept the TPU switch on the mobo wich i put back to off ) then after that, i hit the issue you have and i think a few other members in another post.. 4080 usable, 8196 detected. i really tho it was a hardware prob but when i put both dimm in single channel use, all 8192 ram is there in the bios and windows 8.1 64..
think i will use it in single channel from now on untill i find the answer - and i will post it here

 

[Xibyth]

Go to my computer and select properties, what does it say about your Windows installation, and does it say about your version, please provide an image.

 

[nizhar10]

HI I had exactly same problem as yours. i am using an American megatrends BIOS and it has only 2 RAM slots. I inserted 4x2 gb RAM. Firstly, when i used to look at my system properties(by right-clicking MY COMPUTER> PROPERTIES) i used to see this : MEMORY = 8GB(3.90 GB usable). I tried changing the the Positions of the RAM sticks, inserting new RAMs and changing the GPU. NOTHING WORKED !! i tried asking all the LOCAL COMPUTER TECHNICIANS about this problem but no one helped me... Finally, it was time for me to decide something by Myself . i started the pc, entered the BIOS, got into 'CHIPSET FEATURES', ENABLED THE 'MEMORY MAPPING' , ENABLED ALL THE PORTS, and finally, i used the option 'USE OPTIMUM SETTINGS' on the main BIOS screen. Now, when i start my pc and SEE the properties of My Computer, i see: MEMORY: 8 GB. now, u must be thinking what proof do i have that MY PC is making optimum use of RAM. Well, i may say that My PC & GAMES are working way faster than they used to be. As you are using an ASUS BIOS, i dont know much about ur BIOS. but i ASSURE u that ASUS BIOS are way better than AMERICAN MEGATRENDS and so, u can easily change the settings of ur BIOS. Just look for the Following Options and change the settings. 1) MEMORY MAPPING- enable it ! 2) USE OPTIMUM SYSTEM SETTINGS- Select it and select 'OK' I hope this works and it should