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RSmit20
Beginner
2,619 Views

Memory ranges reported by ACPI

Hello All,

I've got a question and I was just wondering if someone could help clear it up for me.

First of all I am using a Z87 chipset motherboard.

Looking at Device Manager in Windows and I see the following memory ranges when viewing the 'Resources by connection' view-

The question that I have is why are the last 11 items not shown to be on the PCI bus?

It appears that the PAM register ranges are shown to be on the PCI bus (well, those that have not been set to shadow the bios and vbios) such as 0xDC000 - 0xDFFFF.

I understand that the last 20MB of the 4GB address range can't be used as PCI MMIO addresses and is always sent to the DMI interface so maybe that's why they aren't shown to be on the PCI bus...

but am right in thinking that the last 11 devices shown in the above image are forwarded onto the 'PCI bus 0', just like the PAM registers, and then technically they should be shown to be in the PCI bus range?

Also if I click on one of the "Motherboard resources", say for example the one listed between 0xFED18000 - 0xFED18FFF, it shows -

..as you can see it does show it to be on the PCI bus.

The reason I have asked this here is that I assume that Windows just gets these ranges from the ACPI tables given to it form the BIOS writers at Intel.

If anyone could offer any help with this and confirm that my understanding is correct it would be greatly appreciated.

Kind Regards,

Robert

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8 Replies
Allan_J_Intel1
Employee
30 Views

Thanks for joining the desktop community.

It would be very helpful if you could include system specifications:

* Desktop Board:

* Board Altered Assembly Number (AA# ):

* Board Serial Number (SN# ):

* Previous BIOS:

* Current BIOS:

* Power Supply:

* Processor:

* Memory:

* Operating System:

* HDD:

Thanks

Allan.

RSmit20
Beginner
30 Views

Thanks Allan,

The details I could find are -

* Desktop Board: Gigabyte Z87-HD3

* Board Altered Assembly Number (AA# ): ?

* Board Serial Number (SN# ): ?

* Previous BIOS: F6

* Current BIOS: F7 01/20/2014

* Power Supply: 750 Watt

* Processor: Intel Core i5 4570

* Memory: 16GB

* Operating System: Windows 7 64-bit

* HDD: 64GB OCZ-AGIL AGILITY3 SSD

To be be honest Allan it's not an issue with the system, I think Windows is getting the readings from the DSDT ACPI table written by an Intel engineer that is why I am posting here.

I was just wondering if I could speak with someone about why it is displayed like that in Device Manager?

Basically it looks like the PAM register memory address ranges (e.g. 0xD0000 - 0xD3FFF) are shown to be on the PCI bus, but the ranges from 0xFED00000 onwards aren't shown to be on the PCI bus, when I think they are just like the PAM registers.

Again it's not an issue and there maybe a reason for displaying them like this but I would just like to know what it is.

Thanks Allan.

RSmit20
Beginner
30 Views

Hi again,

for example I had a look on another Intel system (I'm not sure of any details) and it showed the following -

It shows that from 0xF0000000 - 0xFFFFFFFF to be on the PCI bus, which I think it should show on mine, maybe this is an error in the DSDT table, or maybe it is like that for a reason?

Thanks.

RSmit20
Beginner
30 Views

Hi Allan,

Any update?

It's also worth noting that the APIC range (0xFEC00000) seems to be missing)

Thanks.

RSmit20
Beginner
30 Views

Hi Allan,

Can you give me the contact details of someone I can talk with this about?

Thanks.

Allan_J_Intel1
Employee
30 Views

Sorry for the delayed answer.

Since your computer is Gigabyte and all the components were integrated by your motherboard maker, you need to check with Gigabyte engineer about this matter, or contact Microsoft for more information on this issue.

If you would like to contact an Intel engineer this has to be through an Intel authorized distributor and work with field application engineers

Here is a list of Intel authorized distributors:

https://www-ssl.intel.com/p/en_US/techprovider/buy-authorized https://www-ssl.intel.com/p/en_US/techprovider/buy-authorized

Allan.

RSmit20
Beginner
30 Views

No worries Alan.

Would it not be Intel that writes the BIOS for the motherboards, or do motherboard makers do that?

Thanks.

Allan_J_Intel1
Employee
30 Views

For Intel boards, you will find Phoenix BIOS and they have developed the BIOS according to the system configuration. At this point, you need to check with Gigabyte for information about your BIOS developer.

Allan.