" Nothing else beside Poser runs during that time."

That's not true, you're running Windows.  And Windows is where Poser's math is calculated.  Poser does'nt have it's own Swap File, and relays on Window's; so Windows gets a pretty good workout, when Poser is around.  Windows XP has a Memory limit of 2GBs, per application; with Windows counting as an application.* * So that 4Gbs of RAM use you're seeing is'nt all Poser.

pjz99 - Applications that are Large Address Aware can receive 3GBs per application, but you would need Vista and Poser 7 to qualify there; unless you go with stewer's work around...

Rhiana - If you're using Vista and Poser the first thing you can look to is your Virtual Memory setting; where you'll, probably, need to increase it's opening size.  Your's should open at at least 2GBs.  This would allow 3GBs for Windows(2Physical(RAM) + 1 Virtual,) and the same for Poser.

The next thing you can look for, even before render settings, are your figures' morphs.  When you Save, as a .PZ3, how big is the scene?  There could, potentially be 100s of MBs wasted by Morphs set to "0".  This is especially true with Daz figures.  If you've got all of V3 loaded, with all of her morphs INJ'd, you're probably bogged pretty bad.  I could shave 190MBs, off a 250MB V3.PZ3, just by removing morphs set to zero; with SVDL's removemorphs.py.  And that's just the quicky.  If you're really interested in conserving space we can get into how I consolidated all of my V3.PZ3 morphs, and ended up saving 240MBs, off that 250MB .PZ3!

I still hav'nt seen the render setting?  I saw the link:

*http://rhian-skyblade.deviantart.com/gallery/#_browse/scraps

*but there are no images there.

Aside from that would you please post a link to PE Explorer?*