not all RAM "usable"

Habedrabbo

Reputable
Dec 31, 2014
55
0
4,630
specs:
MOBO:gigabyte 990fxa-ud3 rev 4
RAM:G-Skill Ripjaws(2x4GB) 1600
PSU:Gigabyte Greenmax plus 550W 80+ bronze
CPU:AMD FX8350
GPU: Sapphire Radeon R9 280
OS: Windows 8.1 64bit

Problem:

The issue is as stated in the thread title. I go to properties and find that 8GB of memory are detected but only 3.92GB is "usable." And yes they are seated properly; I know Google is my friend, but the "solutions" I have found are not working. The common solution I have found is going to msconig and changing the max setting in the advanced boot RAM options.
This hasn't worked, I've also tried to make some changes in BIOS but I'm no computer tech so I don't know which to switch. I've just been changing options that sound like they would make an effect but that's not the case. Another answer i have read is that there might be a bad stick of RAM but no, both boot up fine by them selves and the system detects 8GB's.
I have also looked at Gigabyte's compatibility with the RAM but according their site the info is outdated and they don't want to put all the RAM info. out there since there's so many options(don't blame them). So unless I'm missing something completely obvious to the pro's eyes than an amateur like me hasn't seen or tried please go ahead and suggest. I'm just a little irritated I spent about 70 USD on this RAM and cant seem to use it all.

NOTE: This is a new build and my first any suggestions about the problem or enhancing the overall system in it's current state in anyway is greatly appreciated. Also; haven't read any where that this would even be a problem but, I have updated and downloaded all current drivers.
 
Solution


Yeah that's pretty consistent with a faulty DIMM or DIMM socket. The 8GiB is coming from the SPDs, not the total amount mapped into the address space.

Check each DIMM in each socket, make sure that every combination works.
Are you absolutely sure you are running a 64bit OS? It should be all usable in a 64bit OS if it is detected. A 64bit OS would state System type as 64-bit Operating System, x64 based processor under System in the control panel. If it doesn't say this you may have installed the wrong OS version (if you bought retail there should be two disks a 32bit and 64bit version.
 
Alot of suggestions, thanks in advanced. Justin Milard, it says 8GB available almost 4GB usable total and my BIOS doesn't clearly say that it is in dual channel but I do have the RAM in the correct slots for such. Syeekick OS is indeed a 64bit bought it OEM and to my knowledge this mobo doesnt have on board graphics and I also have not seen any option in the BIOS for any suggestion towards so. And now that someone has suggested updating BIOS which I overlooked during installation I will try this and update in a few minutes.
 
Press ctrl, alt and del and then open up task manager and click on performance. It should say you have at least 7.8GB available.

The 3.92 number just sounds like the amount of RAM you have usable in each stick of RAM.
The number you get in the task manager should so how much RAM is actually available.
 


Did you try both DIMMs independently in all DIMM slots? The DIMMs may be fine, but that doesn't mean that the motherboard is.
 
I highly doubt this is a BIOS issue. That board being a 4th Rev board only has 3 BIOS's available and only the 3rd one supports new hardware (Specifically the 8320e, 8370e, and 8370) of which you are not using. So support would be an unlikely issue. This again seems likely to an issue with your OS likely being 32bit. (incorrectly shipped disk?) Please check your system information in the control panel to confirm this is indeed a 64bit OS. As this is the most probable cause of this type of error.
 


Nah, it's definitely 64-bit based on the amount of memory that is usable. That GPU is going to carve out a minimum 256MiB MMIO range.
 
OS is indeed 64bit task manager states I actually have 2.5 available 1.8/11.2GB commited 1.4GB in use speed 800MHz slots used 2 of 4 form factor DIMM hardware reserved 4GB and 1.4GB cached or just 1.5/4.0GB
 


Ok this from what I have read seems to be an issue with the timing etc on your memory. Try messing with that in the BIOS. It is an odd issue for sure. As your hardware is reserving 4GB of memory for some reason unknown. As that number should be less than 100MB.
 
syeekick as of right now bills are due next week no money I'm a broke mofo. Jason I tested the RAM and slots when I had to RMA GPU, RAM and slots are fine. caqde the only settings i can change with timings or really any other option regarding memory in BIOS is xmp;which I have already done, the rest are set to auto and I cant change them at all BIOS won't let me. This is starting to sound like some kind of software issue, if that's even possible.
 


What does the POST screen say during startup? It should print the amount of memory that it maps into the physical address space.
 


Are you using the XMP settings? You may want to relax the settings if you are. Your CPU may not like the XMP settings of the Memory and yes you should be able to change the settings. That motherboard will allow you to although you might not know how to. Although I would just check to see if auto without XMP works without the reservation issue.

BTW you can not change reserved memory in the OS. The OS will be told that memory is or isn't reserved by the BIOS it can not reserve memory on its own. If relaxing the settings doesn't work then the issue could be with the motherboard or memory itself. I'd also check your memory with a memory testing program like memtest86.