I did some reading but i didnt see much on the actual use of Zbrush 3 with Vista 64bit… I planned on shoving 8GB of ram into my system but I tried this first… I installed vista 64bit (legit) on a 2nd harddrive on my desktop and when I use Zbrush it lags everytime i go to do anything… Now I have 32bit on my laptop (basically brand new) and I dont get any lag… and it has a 9600M GT… and my desktop has 9800GTX… The only big difference is my desktop is a quad, and has only 2GB of 800mhz dual channel memory, my laptop has 4GB of 800mhz dual channels, but is a dual core… You think using vista with the 2GB of ram is hurting Zbrush ? or maybe I’ll just have to go to xp64bit… or downgrade to 32bit Vista ? :|… I tried doing the flashdrive trick for extra memory… but it only helped everything BUT Zbrush…
only thing I can do is post my specs for you:
Vista 64
Quad 6600
4gb ddr2 800
ati 4870
I have no issues with zbrush
you probably need more ram… vista by itself can eat a whole gig depending on what you’re running.
I’ve got Vista 64 and 8 gigs. Works great. Although I think you can only dedicate 4 gigs to zbrush as of the current version.
i use vista 64bit ultimate on my quadcore intel tower system that has 8 gigs of ram and wacom bamboo medium tablet/pen with nvidia 512 g card…no issues really to use it at all.
What types of poly counts are you getting with all 8 gigs? Although I would think you would need to dedicate 2 gigs to Vista.
well, with 8 gigs you’re capping out zbrush (with 4 gigs). you can get 12mil polys on a single object but when it comes time to generate maps, you may hit some snags (like I did).
just recently I had a large character that was a single object (no clothes or anything to break up the form). I took it up to 11.98mil and finished it off… when I needed to create a normal map zbrush choked on it. memory allocation errors. Ultimately deleting all of my layers, reducing compactmem to 256, and settling on a 3k normal map instead of a 4k map allowed me to generate it.
we REALLY need a native 64bit zbrush, but I’m not holding my breath. So long as pixologic says “we take full advantage of your 64bit system” and people believe it, they have no incentive to make it 64bit 
when i got the 8 gig ram in i did a quick test and it was still responsive at around 15million polys…not a production model but a quick test .
about 64bit…
Mudbox2009 has a 64bit version
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=12068866
modo
looks like it’s still just 32bit
http://www.luxology.com/whatismodo/techspecs.aspx
3dcoat
looks to be 32bit currently
http://www.3dcoat.com/index.html
blender
is 64bit…
http://www.blender.org/download/get-blender/
Vista 64 here. With 8 Gig or ram. No lag. I’ve had over 16 mil and still very usable. Down at 6 mil its flys. I agree, 2 gig is your problem.
Do I understand it correctly?
If I have a 64 bit machine running windows xp 64 and have 8 Gb of ram I am slightly better off than if I have 8 Gb of ram because I can give Zbrush the full 4 Gb of ram because Zbrush can only handle 4 Gb at this stage?
If that is true why dies Pixologic say that Zbrush is 64 bit compliant?
I mean that is just silly - is it not?
Am I correct in these assumptions?
Thanx
it’s called ‘marketing spin’… if they say it and we believe it, then they don’t have to actually DO it 
The real reason to use Z3 in a 64bit environment is this: in a 32bit OS, you’re limited to 3GB total- and of that your operating system, and all the other little apps you’re running will eat into that. What’s left over is what ZBrush has access to. So even though you’ve capped out your 32bit system, ZBrush might still only have access to 2GB of memory… and through the trickery of memory priority and page files and whatnot, they get around this for the most part by compacting mem.
however in a 64bit OS, you can have up to 128gb of RAM, and even though ZBrush can only use 4gb of that memory, if you put 8 gigs in your system you can be sure that ZBrush has a full 4gb to work with. Plus you can have photoshop open, ZBC, and all kinds of other stuff 
Also- 12mil polys is the Z3.1 ‘soft cap’. You can technically overcrank the maxpolypermesh setting in the memory preferences and get up to 20mil polys (if i’m not mistaken), but while sculpting at that highest level you’re going to be dumping to disk fairly regularly (which probably means more unstability of the app). Not to mention there’s pretty much no way you can export a map from a 20mil polygon in Zbrush, as it seems to load the entire high resolution mesh into memory while it maps the normals and whatnot.
Got all that
Yeah, i ran out and bought 2x2GB 800mhz Kingston kit today for only $60… Zbrush flies , and I got it up to 21million polies! (6GB total). I’m gonna go get another 2x2GB kit to bring me up to 8GB. I know zbrush only uses what… 4GB? so 8GB “seems” like overkill… But not when your running all those heavy vista background stuff, Browsers, dual screens, maya, and photoshop! It merely lets Zbrush use that full 4GB all to itself.
I also wondered how much better a quadro is with this stuff than a geforce, i read mostly the quadros are just more reliable, errorless, and will take a vicious beating.
Don’t bother if all you use is ZBrush.
depends on what other apps you run. I use XSI and maya (both native 64bit)… I can tell you that when I need to do a large render or run an AO batch w/ XSI’s ultimapper I am extremely glad I’ve got the extra memory heheh
I dont just use Zbrush, I use Maya, Photoshop, and soon to be some other fluid dynamic based programs like Realflow, and maybe some compositing with Nuke or something. =)