Hi!
I recently switched to 64 bit version of Windows XP and hoped to double polygon count on my Zbrush models but that did not happens. I installed Zbrush 3.0 and upgrade to 3.1.
I looked at task manager and Zbrush was marked with something like (32*) witch i assumed stands for 32 bit application.
How can i make Zbrush run on 64 bit OS?
ZBrush is a hybrid app. In other words, it’s a 32-bit program that is large address aware so that it can use up to 4 GB of RAM.
Simply switching to a 64-bit OS isn’t going to double your computer’s capabilities. All it’s going to do is let you install more RAM in the computer. A 32-bit OS wouldn’t give more than 2 GB of RAM to ZBrush. The 64-bit will give double that. Although if your system has 4GB of RAM then it still needs to reserve some of that for the OS itself.
What’s more, you must adjust Preferences>Mem>Compact Mem before ZBrush will use any additional RAM that your OS is giving to it. With a 32-bit OS this should never exceed 2048. With a 64-bit OS and 4 GB of RAM it should be set to about 3000. With a 64-bit OS and more than 4 GB of RAM it can be set all the way to 4096.
Thanks for this reponse aurick, i was just about to ask this same question but since someone beat me to it, not necessary!
aurick, thats a great tip! thanks!
Thanks for answer you helped my, now i am zbrushing on 4 GB .
are there any plans to make zb a true 64 bit app? ie: take advantage of the larger register sizes and address more than 4Gb of memory etc? if so, will it be any time soon or is this something that’s still a long way off? thanks!
thanks Aurick for clearing this issue … i will be getting 2 sticks of 2 GBs (makes total of 6) and a modest wacom, for my intense zb-ing very soon 
cheers
I was just wondering this since I just got a 64bit OS with 4gb of ram…
So 4 gigs of ram… set compact to 3gigs…
Are there any other settings you find advantageous for 64bit OS’s?
You can double whatever the default MaxPolysPerMesh setting is.