Z170XP-SLI Reserving Memory in Windows 8.1

[Frank Rizzo]

This is a bit of an unusual one. Windows 8.1 32bit (don't jump in there quite yet  ) is only showing 2.10Gb available regardless of how I configure the RAM.

SPECS
Z170XP-SLI
2x4GB Savage Black PC4-19200C12 2400MHz Dual Channel Kit - Black HX424C12SBK2/8
Windows 8.1 32bit (as I said refrain from hitting reply at this stage)

Issue
Windows will only show 2.10GB available in Control Panel System. This happens if:

Both sticks are installed
Only one stick is installed
Only the other stick is installed
Either stick is installed in either of the slots singularly

Evidence
When both sticks are installed Resource Monitor -> Memory shows 6GB as hardware reserved
When one stick is installed Resource Monitor -> Memory shows 2GB as hardware reserved

Testing
1. The BIOS shows 8GB installed
2. CPU-Z reports 8 GBytes intsalled in Dual channel
(I appreciate both the above could just be reporting the SPD figures and not the true 'working RAM')
3. Windows Memory Test passes fine
4. MemTest86 passes fine
5. I ran an Ubuntu Live CD and that reports the full 8Gb as being available
6. F5 and F6 Beta bioses have been used

This is unusual because it is not possible to nail this down directly to the motherboard, RAM, or windows.

It could be that the RAM is not 100% compatible in that it will work, but it only make 2Gb available to Windows 32bit windows.

It could be that the motherboard is not 100% compatible with the RAM and that a BIOS update could fix it.

It could be that Windows 8.1 32bit is the villain here but I find nothing on Google with a similar issue for this board.

Why use 32bit? Use 64bit instead
Because custom apps require a 32bit environment and because it is slightly faster than 64bit (for these custom apps).

Other Rigs are OK
I have a Z87-HD3 with 2x 4Gb of DDR3 ram and this works perfectly with Windows 8.1 32bit. I can see the max available RAM (3.5Gb) that is available to Windows (if anyone is interested the other 4Gb is use as a Ramdrive).

Any ideas? It is perfectly usable with 2.1Gb but it would be nice to find out what's happening to the other 1.5Gb.

[absic]

Windows will allocate a certain amount of RAM from the available 4GB (max in 32 bit environment) for other hardware such as a GPU or on-board graphics and other motherboard hardware items installed, along with some for BIOS

Have you checked Windows Resource Manager to see how your RAM is being used?

For example:


How much of your RAM is under the Hardware Reserved section (coloured grey)? If you are using On-board graphics rather than a dedicated GPU this may well be where the RAM loss is occurring.

[Frank Rizzo]

Yes it is showing 6GB as reserved. Only 4.5GB should (the 4GB "above 4GB" and the ~0.5GB that Windows always takes).

I have tried a dedicated HD5450 and the onboard graphics. In both tests the results are the same.

It seems that no matter what configuration is performed (BIOS defaults, different slots, 1 or 2 slots, onboard GFX, PCI GFX, Windows initial install before correct, drivers are found, Windows safe mode) then exactly 2.10GB is only ever available to windows. This is very unusual because you would think that changing the config slightly would vary the 2.10GB but it is constant.

[absic]

As you say, it does seem very strange. Sadly I don't have a Z170 board my self and I am running Windows 10 64 bit so I can't do any testing to compare results but, hopefully another member of the forum might be able to help with this aspect.

Have you tested with only one of the 4Gb sticks installed to see how much is taken?

What are your full hardware specs?

[Frank Rizzo]

Yes tried all combinations of 2 and 1 sticks and it's always exactly 2.10Gb free.

Specs are in the opening thread along with 950 Pro NVME 256GB

According to the Kingston site the 8GB Kit is compatible with the Z170XP-SLI

http://www.hyperxgaming.com/us/certifications

But on the Gigabyte site only the 16GB Kit is listed in the MSL.

One option is to purchase that kit instead but it seems silly just to test and return it if the problem turns out to be the mobo or Windows.

[Frank Rizzo]

I just installed 64bit windows. It works fine, with only 56MB or so being reserved.

So the issue is with 32bit windows but is not the fault of 32bit windows. Either the motherboard or the RAM is causing windows 32bit to reserve an extra 1.5Gb for some reason.

[shadowsports]

This is very interesting guys.  If you aren't messing with RAM disk or Page File size, could this be related to the way the X170 chipset works with 32bit windows?  Could also be BIOS.  I like Absic's take on reserving memory for hardware.  Might be related to memory allocation for the storage controller or CPU for Pre-Fetch.  I haven't studied the architecture.  Just a guess.  Considering the performance potential there isn't much demand for x86 windows any longer.

[Frank Rizzo]

This is very interesting guys.  If you aren't messing with RAM disk or Page File size, could this be related to the way the X170 chipset works with 32bit windows?  Could also be BIOS.  I like Absic's take on reserving memory for hardware.  Might be related to memory allocation for the storage controller or CPU for Pre-Fetch.  I haven't studied the architecture.  Just a guess.  Considering the performance potential there isn't much demand for x86 windows any longer.

Yes that is sort of what I was thinking but then as these boards have been around for a few months there would surely be other reports of this. Maybe it's only a few extreme users like me who want 8GB in a 32bit windows environment (3.5GB win + 0.5GB reserved + 4GB ramdrive) so it could be the case this is a problem sitting there but no one is experiencing it because no one is doing this kind of setup.

As for BIOS settings I tried all combinations of:

Channel Interleaving
Rank Interleaving
XMP profiles and manual (just clock speed - did not even bother with timings)

Other things I have tried:

Safe Mode - basic drivers
MSConfig -> Boot -> Advanced -> Maximum Memory. This is not ticked. I even tried setting varies levels
Onboard Graphics -> DVMT Pre-Allocated (32M-512M)
Onboard Graphics -> Total Gfx Mem (129M-256M0

For the last two I can get a change in the Hardware Reserved figure. I set both to max and then 6.8GB is reserved leaving 1.35GB usable



Note in this example 4GB is reserved for the "Above 4GB" Ramdrive, 768MB is reserved for onboard GFX. This leaves 2GB unaccounted for.



I think this is one of those issues where if you approach Microsoft they will say "it's the Motherboard", if you then approach Gigabyte they will say "it's the RAM", and then Kingston will say "it's Microsoft".

[absic]

SPECS
Z170XP-SLI
2x4GB Savage Black PC4-19200C12 2400MHz Dual Channel Kit - Black HX424C12SBK2/8
Windows 8.1 32bit

Specs are in the opening thread along with 950 Pro NVME 256GB

Just trying to get an idea of your complete PC configuration, what other devices do you have attached such as USB items (mouse, keyboard), Monitor, DVD/CD drive(s) other HDD's or SSD's, PSU etc. I have learnt that even something that you might not thing can be causing a problem might well be doing so.

[Frank Rizzo]

Ah right. in addition to the above these devices are / were installed:

Logitech Wireless K520 + M705
BenQ G420HDBL (Digital)
NVMe Samsung SSD 950
Samsung HD103SJ HDD
AMD Radeon 5450 (this has been removed to isolate it)
Leadtek WinFast DTV1000 S (this has been removed to isolate it)
CS450M PSU

[absic]

Well, I can't see anything in your list that could be taking that much RAM.

Have you tried adjusting your Paging file size, as referred to by shadowsports to see if this has any major impact?

To be honest I am only suggesting things that I would be trying in your situation as I haven't come across this particular kind of problem and I don't use a 32bit OS and haven't since the first 64 bit OS's came along. I will continuing browsing the internet to see if I can come up with anything tangible to help you resolve this.

[Frank Rizzo]

We can rule out the RAM. I tried a set of Corsairs in there and it is still the same.

So it is either the motherboard or Windows 8.1 32bit.

Will just have to put up with it.

[Frank Rizzo]

Rule out:

Windows 8.0
Windows 7

They all produce exactly the same result:

Installed memory (RAM): 8.00 GB (2.10 GB usable)

---

This is now very likely to be the mobo but I would have thought others would have experienced the same issue. But then there must be very few out there who require 32bit windows with these modern rigs.

It is thus more likely that this is a bug or flaw with this board, or Z170s in general, which users would never know about because they are running 64bit. Manufacturers won't fix it because hardly anyone is reporting the flaw to them.

[Frank Rizzo]

I contacted Gigabyte support. They were pretty quick in resolving this issue.

A BIOS update fixes it.

Thanks to all who took time to assist with the diagnostic here.

[shadowsports]

Nice of you to reply back with the solution.  Can you please post what BIOS version resolved the issue for other's benefit please.

Cheers!