Question Why only 24gb is usable out of 32?

[ozzi3]

Hi,

Weird findings. I tested each stick one by one (all 4 of 8gb) changing slots. While they work well each (read as 8gb), some is not working on some slots (cpu fan went slow, can't access bios). So I marked which slot works with which stick. Then I started again with only 2 of them. Now it began to mess up as only 8gb out of 16gb is usable. I added another two and it's written as 24gb being used. But bios and the task manager can recognize all the 32gb ram. It's just the other 8gb is reserved for the hardware as the task manager tells.

I think I've done everything to fix it -- from updating bios and windows, command prompt fix, msconfig, replacing cmos, cleaning the dust. Nothing can make it fully work. Have I missed something? I suspect the motherboard since I have an old PC from 2014.

MB: Gigabyte 970a-d3p
CPU: AMD FX 6300
RAM: 4x8gb Team Elite plus (ddr3) 1600mhz
PSU: Cooler Master elite v4 80plus 600W
GPU: 2gb nvidia geforce gt 730
SSD: 3x256gb adata su800
OS: windows 10 pro 64bit

 

[Aeacus]

Weird findings. I tested each stick one by one (all 4 of 8gb) changing slots.

Those DIMMs are? Or better yet: Full system specs, including PSU make and model (or part number) is? Also, how old the PSU is, and was the PSU bought new or used/refurbished?

Did those DIMMs came in a set of 4, or are they individual sticks?

 

[SkyNetRising]

I think I've done everything to fix it -- from updating bios and windows, command prompt fix, msconfig

Can you show a screenshot with your settings from msconfig?
(upload to imgur.com and post link)

Maximum memory checkbox in msconfig/boot/advanced has to be cleared.
Save/reboot after changing settings.

What is model name of your motherboard?
You can find it with CPU-Z - motherboard section.

If it is with Intel LGA cpu socket, then check cpu socket for bent/broken pins.
Make several high resolution photos from different angles and show here.

 

[ozzi3]

Those DIMMs are? Or better yet: Full system specs, including PSU make and model (or part number) is? Also, how old the PSU is, and was the PSU bought new or used/refurbished?

Did those DIMMs came in a set of 4, or are they individual sticks?

OK. Post edited.

 

[ozzi3]

Can you show a screenshot with your settings from msconfig?
(upload to imgur.com and post link)

Maximum memory checkbox in msconfig/boot/advanced has to be cleared.
Save/reboot after changing settings.

What is model name of your motherboard?
You can find it with CPU-Z - motherboard section.

If it is with Intel LGA cpu socket, then check cpu socket for bent/broken pins.
Make several high resolution photos from different angles and show here.

I got it unchecked, including on the core setting. And there is no broken pin. I just edited the post for full PC spec. Thanks.

 

[Aeacus]

RAM: 4x8gb Team Elite plus (ddr3) 1600mhz

I'll ask my 2nd question again, since this is important;

Did those DIMMs came in a set of 4, or are they individual sticks?

Or in other words; did you buy the RAM as four individual sticks?

Two sets of two?

Or did all 4x DIMMs came in one, sealed package?

 

[ozzi3]

I'll ask my 2nd question again, since this is important;

Or in other words; did you buy the RAM as four individual sticks?

Two sets of two?

Or did all 4x DIMMs came in one, sealed package?

Yes. 4 individual stick. I also bought the psu new but i can't remember how old it is.

 

[Aeacus]

PSU: Cooler Master elite v4 80plus 600W

This is crap quality PSU and i'd replace it ASAP. Before it goes "boom" and fries your entire system. It may even catch fire. It is so bad.

Good PSUs to go for, are: Seasonic Focus/Vertex/PRIME, Corsair RMx/RMi/HXi/AXi, Super Flower Leadex Gold/Platinum/Titanium.
Or, for bare minimum: Seasonic Core, Corsair RM/RMe/CX/CXm/CXf.

For 2nd opinion about your PSU, look it up from PSU tier list,
link: https://forums.tomshardware.com/thr...er-list-rev-14-8-final-update-jul-21.3624094/

You'll find yours under Tier E! So, do replace it.

But back to your RAM issue;

Yes. 4 individual stick.

With 4x individual sticks, there is 0 guarantee that they all work together. And as you've found out, they don't work all together. Out of 32GB, only 24GB is usable, which means that one of the 8GB sticks doesn't want to work with the rest.

Sure, system detects that all 4x are plugged in and total should be 32GB, but since all four are individual sticks, they don't all work together. Only 3x of them work together, hence why your usable RAM amount is 24GB.

Further reading about why it is so, here (especially 2nd, "mixed memory" chapter),
article: https://forums.tomshardware.com/faq...y-ram-and-xmp-profile-configurations.3398926/

So, if you want a guarantee that all 4x sticks work together, buy a set of 4. Where all 4x sticks come in one, sealed package.
Have you ever wondered why RAM sticks are sold in a set? I take that you don't.

Explanation time:
When RAM DIMMs are made; same make, model, speed, CL and timings RAMs are tested with each other by RAM manufacturer and those sticks that get along well, are put into sets.
First set to be made is the set of 8x RAM sticks and sold as 8x RAM sticks in a set (e.g 8x 8GB, total of 64GB). If the set of 8 doesn't work, it's divided into half which makes up two sets of 4.
If the 4x RAM sticks do work together, the are sold as 4x RAM sticks in a set (e.g 4x 8GB, total of 32GB). But if the set of 4 doesn't work, it's again divided into half, making two sets of 2.
Two RAM sticks that work well with each other are sold as 2x RAM sticks in a set (e.g 2x 8GB, total of 16GB).
Those RAM sticks that doesn't want to work together at all are sold as single RAM sticks.

So, if you need 4x sticks of RAM, buy the set of 4. Sure you can buy all 4x sticks individually but chances of them all working together would be slim. If you'd get only 2x individual sticks, chances would be 50:50.

With DDR, DDR2 and DDR3, using individual sticks is quite lenient and RAM, for the most part, usually works fine. You can run into issues of RAM not achieving the max rated speed, if it is above JEDEC standard.

But with old RAM, all sorts of shenanigans have been made, e.g running 3x 4GB for total of 12GB or one 8GB alongside 4GB (again, for total of 12GB).

DDR4, in the other hand, isn't so forgiving. Getting different capacity sticks running in one machine is next to impossible. And getting individual sticks working together (despite them being otherwise seemingly identical), is also another headache. So, for DDR4, do get the set, if you need more than one DIMM.

DDR5, is looking to be more forgiving again. Big part of it is the fact, that for DDR5, you do not need 2x DIMMs to achieve dual-channel RAM. Instead, DDR5 is made such, where individual DIMM is already running in dual-channel configuration. This eliminates most of the issues when pairing individual sticks. Still, getting individual sticks operate above JEDEC standard (which for DDR5 is above 4800 MT/s), can still be 50:50 chance.