This is a tutorial to set a limit on how much memory is used. If ganjiry's idea does not work (it's memory remapping) try thid tutorial, just remember, it is written for the opposite of what you want to do. See #4. BSOD After using ASUS Sabertooth 990FX MOBO OC Utility.
Also, check bios and make sure it shows all of your memory.
My ram is a 16gb kit of 4x4gb. Also, this is what I got after 7 hours of Prime95Okey doke! Is your memory 1 single 16Gb kit with 4 sticks or did you buy 2 seperate 8Gb kits? It can cause problems if running 2 seperate kits.
Go into the advance tab of your bios, Select North Bridge and then go into Memory Configuration and check if a setting called Memory mapping(can't remember exact name) is enabled. If not enable it.
If it is already enabled then try raising your Cpu Vcore or Cpu/nb voltage a couple of increments. It will take some trial and error.
I'm not too clued up when it comes to memory though so somebody else may have to chime in for that.
If any of that help's get the full 16Gb showing and it has passed memtest then you won't need to run memtest again unless you overclock your ram. If after you memory is stable and Prime finishes ok you can up your cpu ratio untill it fails Prime. When it fails just raise the Cpu Vcore a tad. For 4.5Ghz using a cpu ratio of 22.5 you should be looking around the 1.440- 1.452v mark but all Cpu's are different and yours may take more or less.
I'm off to bed now though mate, knackered! No doubt i'll be up at silly o'clock though so i'll check in as soon as
I don't use Prime myself so i'm not too sure about the prime results txt but to me its looks like you had a core or 2 drop which is probably down to too little vcore. What voltages and cpu ratio are you using?
You could try upping the Northbridge voltage just a couple of increments, As i said memory is something i know very little about, I had the same issue myself once but it was due to 2x 8Gb kit's not playing nice.
Rounding errors are errors. The test basically runs mathematical calculations (Prime numbers, hence the name). It knows the answers and rounding errors means one or more of your cores came back with a wrong number. A real laymans definition. Usually, as ganjiry says, vcore increases will correct it.
As far as the memory, if none of the solutions worked for you, I would re seat the ram. If bios does not 'see' it, that means it is not detectabe. It has to be able to detect it for any fixes to work. If reseating does not work, I would pull 1 stick at a time and see how much is detected. Theoretically, when you pull the stick it is not detecting, it will read the same as it does now. So, pull the stick 1 at a time. If it is not the bad stick, put it back in the same slot and pull the next stick. Keep doing that, and replacing sticks in the same slot, until you find the offending stick. Next, I would mark the bad stick with a small sticker or something and remember the slot it's in. Swap all the sticks around with each stick in a different slot. If you end up with the same problem, pull the stick you marked. and see if you still show 12GB. If you do, that stick is bad and just RMA the entire kit. If you find that stick is not the problem, put it back in the same slot and pull the stick that was in the slot where the bad stick used to be after replacing the stick you marked. If that shows still 12 GB of ram, it is the motherboard dimm slot. I know that is a little confusing, but logical. If you have any questions at all, feel free to ask. If either of us know the answer, we'll be happy to answer. Otherwise we will be happy to find someone who does know the answer. What I am trying to do is determine if you have a bad stick of ram or a bad Dimm slot. That is usually done with memtest86. But memtest can't check the stick for errors unless it can 'see' the stick.
EDIT: ganjiry and I prefer AIDA64, but it is not free although there is a 30 day free trial.You can use whichever one you want. They will both work. AIDA just has many more features. When running these tests, always have your CPU temp monitoring program open and CPUz as well. Take notice of the Core voltage in CPUz while the test is running, it will be different than what you set in bios. We will be asking the values of both as we go along.
Thanks for the info Steve, Good advice mate! It's very much appreciated mate
I think all his ram is showing in the bios which is why i'm thinking voltages as 4 sticks is more stress on the imc but as you know it's all trial and error isn't it.
@huonub, Welcome to the stresses of overclockingyou need the patience of a saint.
I fixed the ram issue. I set the voltage to v1.650 in DRAM, and I switched all the RAM sticks around into different slots(i believe re-seating them actually fix it). System now shows 16GB usable in Windows properties. So after reviewing the corsair ram guide, 1333mhz is v1.500, so should 1600mhz be v1.650? I got this number from CPUID. Thanks for all your help. Also, in terms of my cores dropping off. Which voltage am I adjusting, and by how much in increments? Thanks again for all your help and advice! You are guys freaking awesome.
huonub, Please tell us what the values are in bios for your CPU voltage. FSB, HT link and the CPU-NB. If you can, tell us what those voltages show in CPUz during Prime. ganjiry will have to tell you the values that need to be altered, but he will need to know what the values they are now.
Okay, give me an hour. I'll get them. from BIOS.
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