I do see a lot of misinformation here, I'll try to correct most of it.

First of all, for XP 32 the 3GB /Large switch mentioned is very wrong information, that is for XP Pro, not XP32. If you have WinXP 32 SP3 and you have a new laptop with 4Gb, XP32 SP3 will see and use 3.5Gb of that. Whatever you do never use the 3GB /Large switch on XP32! It's for XP64 only!

Secondly your not better off with Vista 64 on a 64 bit laptop, actually not at all. First of all, even though you have 0.5 Gb more RAM available, that (and more) will be swallowed up by Vista itself. With Vista 64 and 4GB RAM you will have less then 3GB available, unless you tweak Vista to the extreme, With XP32 you will have a little more then 3GB available.

Thirdly, speed. XP by far is faster then Vista will ever be.

Fourthly, even though you will still have the 2Gb per application limit in XP32, for Poser that is not a problem at all. Poser can render in a seperate process, in theory freeing up 2GB for Poser and 2GB for FireFly. Rendering will be assigned it's own memory. Because of this and due to you only having 4GB of RAM, Vista64 will offer you absolutely no advantage at all.

I'll explain. Vista gives the whole full 3GB to Poser (not completely since there's no 3GB left, but makes things easy to explain). If your scene is using 512MB of RAM, you have 2.5GB left for rendering. But..... you will never need that, most likely only 1-1.5Gb. If your scene is 1GB, you will have 2GB left for rendering and probably you need it. If your scene is 2Gb, you only have 1Gb left to render and most likely Poser will crash.

Now to XP32. XP  gives the 2 maximum 2GB to Poser. If your scene is using 512MB of RAM, you have 2GB left for rendering in a seperate process (note the difference). But..... you will never need that, most likely only 1-1.5Gb. If your scene is 1GB, you will have 2GB left for rendering and probably you need it. If your scene is 2Gb, you only have 1Gb left to render and most likely the FireFly engine will crash, leaving Poser running, so you can still save a scene.

You can also assign rendering in a seperate process in Vista, but nothing much will change.

The thing is the 4GB of system ram. If that's all you have and all you can have, which is the case on most laptops, there will be no advantage at all in using Vista or XP64 when it comes to using Poser. With other apps this may differ, but the designers of Poser were clever enough to deal with the whole memory issue on XP, by allowing FireFly to run in a seperate process.

Fifthly.... Poser is still a 32 bit application and there for is limited in the memory it can use. A 64 bit system will not change that. Only if you have Poser Pro, FireFly will be 64bit and can use more then 3GB of ram. If you're on regular Poser, you will always be limited in ram usage. Some apps can use only 2GB, some 3GB and a few 4GB, I'm not sure how it is with Poser.

Lastly..... when running a 32 bit application on Windows 64, Windows will go use an emulattor to run 32 bit applications. Practically.....  your 32 bit application will run a bit slower compared to running in a 32 bit OS.

Enough info I guess.

If your system has more then 4GB of ram installed, the whole story is different and 64 bit is recommended. It also depends a little on the apps you use, but since likely most will be 32 bit, you will not see much advantage.

My laptop (very new), came with Vista installed. All ran smooth (with some annoyance because of the way that Vista works), until the first large Poser scene. Poser crashed, Vista crashed and I went back to XP SP3. You may have to look around for drivers, but most manufactors will have a XP driver set for the laptop. I'm glad I'm back on XP. Vista took a lot longer to do everything it does, XP responds and loads much faster. Applications open quicker. My daughter has a similair laptop, but by the time Vista has started on her system, I've got Poser running (and opened the first scene), checked my email and started browsing the internet.

As for Poser stableness...... Poser is not more stable on a 64bit system at all as someone mentioned. Poser was written for 32 bit and operates best on 32 bit. It runs fine on 64 bit also, but in my experience it's sligly more stable in a 32 bit enviroment.

Artwork and 3DToons items, create the perfect place for you toon and other figures!

http://www.renderosity.com/mod/bcs/index.php?vendor=23722

Due to the childish TOS changes, I'm not allowed to link to my other products outside of Rendo anymore :(

Food for thought.....
https://www.youtube.com/watch?v=pYZw0dfLmLk