Vista Remapping options

[Job]

Trying to install 4gb Ram on Vista HP 64bit - does anyone know how to disable Hardware remapping and enable software remapping? My Bios only has the one MMIO option and I was assuming that S/W remapping could be enabled though windows itself??

Thanks in advance!

 

[NewMaxx]

Here's some background information for you on this:

http://support.microsoft.com/kb/929605

http://www.microsoft.com/whdc/...ver/PAE/pae_os.mspx#EW

My summary:
Physical Address Extension (PAE), which allows for more than 4GB of addressing by extending a 32-bit address space to 36-bit, is not supported on 64-bit operating systems. Technically it is enabled since Vista x64 makes use of Hardware DEP (with an appropriate processor), which requires extension, but this is actually a function of the x64-based OS and not a separate PAE mode. Hence, any limitation imposed on addressing size in such an OS is caused by the motherboard's lack of hardware remapping support.

 

[Nothinman]

Trying to install 4gb Ram on Vista HP 64bit - does anyone know how to disable Hardware remapping and enable software remapping? My Bios only has the one MMIO option and I was assuming that S/W remapping could be enabled though windows itself??

That's a bad assumption, if Windows could enable/disable the remapping at runtime it would also have to support hotplugging of memory to add/remove that memory at runtime and I don't believe it does. Also on PCs the BIOS e820 tables describe the memory layout and if the remapping isn't done before the BIOS sets up those tables I don't think there's any way for the OS to figure out how much memory to remap.

Physical Address Extension (PAE), which allows for more than 4GB of addressing by extending a 32-bit address space to 36-bit, is not supported on 64-bit operating systems. Technically it is enabled since Vista x64 makes use of Hardware DEP (with an appropriate processor), which requires extension, but this is actually a function of the x64-based OS and not a separate PAE mode. Hence, any limitation imposed on addressing size in such an OS is caused by the motherboard's lack of hardware remapping support.

That's wrong, AMD64 OSes don't use PAE at all since NX is built into the architecture when running in long mode.

 

[NewMaxx]

My first sentence stated that PAE "is not supported on 64-bit operating systems" - I was merely trying to explain that while in both cases the same function is served, that of address extension, x64 does it natively and without "a separate PAE mode." This is an important comparison because it means that with either OS he will still need motherboard remapping support, but that the PAE switch is only required for the 32-bit OS.

In any case, I believe Vista 32-bit still limits you to 3.25GB at best regardless, in order to mitigate 32-bit signed driver errors from address extension (common with PAE), which are protected by DEP/NX, in addition to reserving the space for mainboard/video resources.

 

[Nothinman]

And you also said "Technically it is enabled since Vista x64 makes use of Hardware DEP (with an appropriate processor), which requires extension" which is false.

In any case, I believe Vista 32-bit still limits you to 3.25GB at best regardless, in order to mitigate 32-bit signed driver errors from address extension (common with PAE), which are protected by DEP/NX, in addition to reserving the space for mainboard/video resources.

Yes, 32-bit Windows clients aren't allowed to touch addresses >4G which means remapping is irrelevant in that case. Although the amount of memory that you'll see is hardware dependent so 3.25G may or may not apply to the OP.

 

[Job]

Originally posted by: Nothinman

Trying to install 4gb Ram on Vista HP 64bit - does anyone know how to disable Hardware remapping and enable software remapping? My Bios only has the one MMIO option and I was assuming that S/W remapping could be enabled though windows itself??

That's a bad assumption, if Windows could enable/disable the remapping at runtime it would also have to support hotplugging of memory to add/remove that memory at runtime and I don't believe it does. Also on PCs the BIOS e820 tables describe the memory layout and if the remapping isn't done before the BIOS sets up those tables I don't think there's any way for the OS to figure out how much memory to remap.

Physical Address Extension (PAE), which allows for more than 4GB of addressing by extending a 32-bit address space to 36-bit, is not supported on 64-bit operating systems. Technically it is enabled since Vista x64 makes use of Hardware DEP (with an appropriate processor), which requires extension, but this is actually a function of the x64-based OS and not a separate PAE mode. Hence, any limitation imposed on addressing size in such an OS is caused by the motherboard's lack of hardware remapping support.

That's wrong, AMD64 OSes don't use PAE at all since NX is built into the architecture when running in long mode.

Hmm yeah I've gone in to the whole PAE issue through bcdedit - unfortunately I dont actually know the whole mehanics behind how everything works - i think I've found the solution tho if you read my other post

http://forums.anandtech.com/me...id=34&threadid=2082818

any further tips would be much appreciated as even at stock everything seems fairly unstalbe - maybe a ram timings issue? Im at 3-5-5-10

 

[Nothinman]

It's got to be a hardware issue, well I guess it could be a BIOS bug but that seems unlikely.

 

[Job]

Many NF4 boards dont like certain RAM dividers - I think with 4 sticks I'll be very limited - It seems to me that most ppl running 4gb in vista have newer intel boards - def not a bios prob.

EDIT - Mobo supports remapping - this was the first thing i tried, and had limited success (at least I saw more than 3070 mb - problem seems now to be a divider/timings issue - see above link)

 

[VirtualLarry]

Originally posted by: Nothinman
That's a bad assumption, if Windows could enable/disable the remapping at runtime it would also have to support hotplugging of memory to add/remove that memory at runtime and I don't believe it does. Also on PCs the BIOS e820 tables describe the memory layout and if the remapping isn't done before the BIOS sets up those tables I don't think there's any way for the OS to figure out how much memory to remap.

I don't know what version, but there is some version of Windows that supports hot-add memory. I thought that it was Server 2003, but I'm not sure. Does anyone know if Vista supports that?

It is S2003: http://www.microsoft.com/whdc/.../hotadd/hotaddmem.mspx

 

[Nothinman]

I don't know what version, but there is some version of Windows that supports hot-add memory. I thought that it was Server 2003, but I'm not sure. Does anyone know if Vista supports that?

It is S2003: http://www.microsoft.com/whdc/.../hotadd/hotaddmem.mspx

But if you look at the two requirements listed I'll bet you that the OP's, and most hardware out there, doesn't do either of those things. Frankly I'm surprised that it's not just in Datacenter edition.