Optimizing 4GB of RAM. T61p

Hey.
I put 4GB of memory in my T61p, because I plan to dualboot Vista64.

Anyway, while I'm in XP Pro, how can I maximize and optimize my 4GB?

Use the /3GB switch? Does this help? Make things worse?

Does having so much RAM on an XP Pro machine affect it adversely?

I read about using RAMdisk software and pointing it to the extra 1GB of RAM as a Page File instead of using HDD space. Is this a good option? (superspeed.com)

When checking nVidia control panel's "About nVidia Settings" (right click nVidia Settings icon in taskbar), it shows 'Total Physical Memory Available' AND 'Free Physical Memory' as being 2GB. What's up with that??


And also, what should my Page File be set at?? Windows "recommends" 4605 MB. Do I really need this much? What do you have yours set to?

Anyone have any thoughts on these points? I would GREATLY appreciate your help in this matter.

Cheers. . .

 

Using the /3GB switch allows programs to use more that the 2GB limit imposed by the OS. In my reading, that switch typically causes more problems than it is worth as there are some side effects that can really screw up the system as it has the potential to screw with the OS's stack in RAM. Additionally, PAE (Physical Address Extension) is also a little bit of an annoyance from what I hear for similar reasons...so only use it if you really really want to.

There is no such thing as having too much RAM, so no 4GB+XP really isn't a bad thing. It is a good thing, because anything 2GB and up XP is going to perform optimally...and having 4GB just lets you run more programs (and larger programs) without having to resort to the HDD swap file.

Not sure about RAMdisk...never heard of it.

Also, regarding the page file...your PC can only address 4GB of RAM and page file when it is a 32bit system. You need a page file, that much is obvious and it is required by some programs. But if you have 3GB+ of memory it is really only a good idea to set a 1-2GB page file...1GB minimum, 2GB to play it safe in case I am wrong. In my system, I have 2GB of RAM and a 2GB page file...and anything more is a waste. Windows only recommends that much based on a dumb calculation done by the OS that doesn't take into account hardware and software limitations when addressing memory.

 

Greg,
Thank you so much for the answers!

I have since removed the /3GB switch that I added. I noticed that even before messing with this, System Properties shows "Physical Address Extension" beneath the CPU speed and amount of RAM. I think I read somewhere that XP Pro SP2 has this PAE enabled by default. Do you recommend I find out how to turn this off?

Page File I have since set to 2GB. I'm wondering if anyone else reading this has experience in setting the Page File to 3GB in a case similar to my own.

RAMdisk is something I ran across searching Google for answers. www.superspeed.com has a program called RAMdisk that allocates up to 3GB of RAM for use as a Page File source (instead of using HDD) before Windows is able to see the 3GB. In Theory, from what I understand, you can set this RAMdisk to point your pagefile to 1GB of RAM (instead of HDD) and still have Windows see and use the 3GB, thereby utilizing all of your 4GB of RAM AND speeding up the PageFile exponentially.
I'm hoping to find more unbiased information and reviews on it, its advantages and disadvantages and any problems it may cause.

Hopefully someone around here has tried RAMdisk??

Thanks again, Greg, for replying.

 

PAE is not enabled by default and in order to enable it you need the /PAE (or /NOEXECUTE) switch.

I don’t believe that RAMdisk will be able to access the unused 1GB without /PAE enable. And if you have PAE enabled why would you want to use a RAM disk?

By default windows 32 bit allocates the address space to 2GB for application and 2GB for Kernel. When using /3GB switch windows will allocate 3GB for application and leaves 1GB for Kernel and most problems starts when the Kernel needs more than 1GB.

The PAE switch is probably a better choice as it should allow your system to see the 4GB of RAM and utilize it better. For most applications (except for the ones that were developed to support PAE) the 2GB limit will still be intact, but multiple applications could use up to 4GB. It is not a perfect solution, as far as I know most problems with PAE are drivers that do not support it and could prevent the OS from booting. Now, that was mostly back when PAE was initially introduced, I would expect most manufactures to have their drivers updated today.

I must say that this is all a theory for me and I have never tried using the /3GB or /PAE switches.

I hope that helped.

 

I assume you're talking about 32-bit XP. PAE isn't needed on x64

PAE is enabled by default on XP SP2 because it is required for NX/DEP support.

http://support.microsoft.com/kb/875352

/3GB has nothing to do with seeing all your physical RAM. Don't turn it on. Also, you will never see the full 4GB on a 32-bit Windows OS, it's just a hard-coded limitation.

 

The ramdisk can help if whatever work you have is entirely on the ramdisk (like a scratch disk on photoshop or stats program). But to put the page file on the ramdisk is not really going to improve performance. It is better to have ram free for that purpose than use 1GB for page file only. Ramdisks lose its contents after a reboot (like regular ram).

I don't think Lenovo has XP 64-bit drivers for the T61 so no Windows XP Pro x64.

 

interesting. thanks everyone for the replies.

i noticed the nodetect optin switch in the boot.ini, but no PAE. Although, it appears PAE is enabled by what I saw in System Properties, as noted above, and by the fact that SP2 has PAE enabled by default.

Thanks again!

 

My Exchange and SQL boxes beg to differ.

 

Sorry, meant to say Windows *client* OSs.

 

Stash, thanks for correcting me, PEA is indeed enabled by default - In the past 2.5 years I have been primarily working on x64 and I wasn’t paying attention to the 32 bit world. It seems that the PEA behavior was modified by Microsoft since SP2 in order to eliminate driver computability issues (so the /NOEXECUTE could be enabled by default) and also limited PAE to support up to 4GB– In the past PAE allowed 32 bit windows to see more than 4GB.
Now, I remember reading in some forum that one user reported that he could only get his Windows 2003 SP1 server to recognize 4GB by adding the /PAE switch…