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Get Windows XP x86 to recognize more than 4Gb with PAE?


AnX

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Installed this onto my machine and mother's laptop, hers is an Intel Celeron 1007U with HD graphics, both work just fine. My main system is an AMD FX-8320 with an AMD R7 260X GPU (gonna install a 750 Ti as radeon graphics support is mediocre).

A PSA: Hibernation does not work at all with PAE. Standby only works while using certain Radeon/Intel GPUs, and all nVidia GPUs.
If you can live without the above two, you're good.

Edited by AnX
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@bluebolt:

Fact is that the mods discussed in this thread remain unreliable.

 

OTOH, simply activating /PAE on boot.ini and adding a Gavotte ramdisk using PAE remains a good option for those using XP x86 and having more than 3.2 GiB RAM. If the resulting ramdisk is big enough, after setting DisablePagingExecutive=1, one can even put the pagefile in it, besides things like the Temporary Internet Files...

 

BTW: Gavotte Ramdisk Version History and Read Me in English.

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Indeed, but if you guys don't encounter critical (to you) problems with usb devices, you may be sure that it's worth it. PAE works quite well, better than a page file on a ram drive. For example, VirtualBox can't use page file, but takes advantage of PAE.

 

Ps: also, xp doesn't use the page file very well, imho, because it tries to avoid swapping data to the page file, so you will hardly benefit from your page file even if you put it on a ram drive. I know because I used that solution for a couple of years before trying the PAE patch.

Edited by noric
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@bluebolt:

 

Fact is that the mods discussed in this thread remain unreliable.

 

OTOH, simply activating /PAE on boot.ini and adding a Gavotte ramdisk using PAE remains a good option for those using XP x86 and having more than 3.2 GiB RAM. If the resulting ramdisk is big enough, after setting DisablePagingExecutive=1, one can even put the pagefile in it, besides things like the Temporary Internet Files...

 

BTW: Gavotte Ramdisk Version History and Read Me in English.

 

 

Thank you, dencorso, your post had caught my attention.

 

In regards to the “DisablePagingExecutive” link, I’m wondering whether that step is specifically required when using the Ramdisk for paging, or is it merely mentioned as a performance enhancement that should be used in any event?

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... xp doesn't use the page file very well, imho, because it tries to avoid swapping data to the page file, so you will hardly benefit from your page file even if you put it on a ram drive. I know because I used that solution for a couple of years before trying the PAE patch.

 

Were you using the page file in unallocated  RAM?

 

With 8GB RAM physically installed in a 32-bit system, I thought I needed PAE to “open up” (i.e. make available) all 8GB; from there the plan was to use 4GB for RAM in the conventional sense, and use Ramdisk to set up the other (unallocated) 4GB for the page file.

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... xp doesn't use the page file very well, imho, because it tries to avoid swapping data to the page file, so you will hardly benefit from your page file even if you put it on a ram drive. I know because I used that solution for a couple of years before trying the PAE patch.

 

Were you using the page file in unallocated  RAM?

 

With 8GB RAM physically installed in a 32-bit system, I thought I needed PAE to “open up” (i.e. make available) all 8GB; from there the plan was to use 4GB for RAM in the conventional sense, and use Ramdisk to set up the other (unallocated) 4GB for the page file.

 

Yes, I was. I used Primo Ramdisk for that. It can create a ram drive in unallocated memory. No need for PAE if that's what you're after. But be aware that xp doesn't let programs swap very much.

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In regards to the “DisablePagingExecutive” link, I’m wondering whether that step is specifically required when using the Ramdisk for paging, or is it merely mentioned as a performance enhancement that should be used in any event?

By disabling the PagingExecutive one prevents the Kernel and all Drivers from being paged by Win NT. Other things continue to be paged normally. Now, since the Gavotte Ramdisk is itself implemented as a Driver (viz. rramdisk.sys), one cannot risk allowing the OS to try to move that driver to the pagefile, because it actually holds the pagefile in itself and, hence, the the system will crash on attempting it. However, there no sure way to prevent the OS from moving just rramdisk.sys... the best that can be done is to disable the PagingExecutive, and it works great.

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Wonderful, thanks.

Next:  my understanding is that when one uses PAE on a 32-bit system with, for example, 8GB of RAM, the system can then use all 8GB, but there is a drawback (so-called PAE overhead) compared to a 64-bit system with 8GB of RAM.

 

Question:  if we only use 4GB of RAM as such (using the other 4GB for a pagefile), do we still encounter the overhead?

 

https://msdn.microsoft.com/en-us/library/windows/desktop/aa366796%28v=vs.85%29.aspx

[“With PAE, the operating system moves from two-level linear address translation to three-level address translation.”

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... there is a drawback (so-called PAE overhead) compared to a 64-bit system ...

 

Yep the PAE overhead adds some drag, specially in floating point performance. See this comparison of Se7en x86 vs x64 running Linx, both on same system with 16GB of RAM:

 

http://www.msfn.org/board/topic/171177-xp-to-vista-is-it-worth-it/page-3#entry1075735

 

That said, in typical use the 'seat of the pants' is very similar.

 

 

Question:  if we only use 4GB of RAM as such (using the other 4GB for a pagefile), do we still encounter the overhead?

 

Yes, plus the overhead from the ramdisk application. But you may not notice any extra drag. In fact if you move the pagefile, enviroment variables %TEMP% and %TMP%, etc. to ramdisk you'll most probably feel it faster.

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  • 3 weeks later...

However, there no sure way to prevent the OS from moving just rramdisk.sys... the best that can be done is to disable the PagingExecutive, and it works great.

 

I belived that windows (and other OSes) use non-paged pool memory for critical things like ISRs and drivers to prevent be paged out. What do you exactly mean by "disable the PagingExecutive"? You mean disable page file in control panels?

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