I am getting a dual processor tablet PC with Vista 64 but first I need to know how much RAM can be allocated to ZBrush. That is, can ZBrush actually use more than 4GB of RAM? Thank you.
Dont think it can. However, you need to have more than 4 so that ZB can get a full 4 gig. I would go for 8 if I were you.
Thanks for the info. I have a pretty good deal on the machine I want, and then I think I will upgrade it to 8GB later.
I’ve got 8 gigs on my vista64bit system and ZBrush runs like a dream.
I wonder though, if 16 or more gigs would make it even better…
What are the other specs of your system? Is it a desktop?
Yes, it’s a desktop with 2 dual core Xeon 5140 and a quite old 7900gtx card. I was amazed to see the tremendous increase of performance when I switched from XP 32bit with 4 gigs to Vista Ultimate 64bit with 8 gigs.
Not only it can load much higher polycounts, it renders them much faster now.Awesome.
Your XP32 machine would give zbrush a max of 2 gig (or 3 if you had the switch enabled), with you Vista 64 it would get all it could take.
So, there is actually point of using the maximum available memory that my board can support (32gb) 
it wouldn’t change anything… not until zbrush becomes native 64bit that is.
Zbrush can only use 4gigs of RAM… period. so having more than four is nice, because then you can give 1GB to your OS, and an additional amount to any other programs that are running, but ZBrush will still only ever use 4GB. 16GB (or 32 for that matter) would be a waste of money, unless you’re buying it for another program that is actually native 64bit (such as mudbox, Max, Maya, XSI, every other 3D software on the market basically).
I see… nevertheless, even with just 4 gigs, running -not native 64bit-ZBrush on 64bit is much much more preferable than on 32bit.
Even in comparison with its (native 64bit) opponents, 32bit ZB is more efficient, being the only one to load big obj models (over 500 mb) and handle them.
OK this is helpful. So, what about 6 GB, would that be good if I am only running ZBrush, or does the RAM need to be in even blocks, such that I would have to get 8 GB in order for ZBrush to utilize 4GB? This would be on a dual core machine.
Thank you.
Well, I guess this is a matter of your motherboard specs… some of the latest ones, afaik, do support a maximum of 6 gigs…
After all, we always have a good excuse for more ram! hehe
I personally run 8 gigs, just because 2 gig sticks are incredibly cheap right now… after rebates my 8 gigs cost me under $100, and it’s quality corsair stuff. ZBrush gets it’s 4 gigs, and I still have a few gigs left over for running other things with ease… I find 8 to be a nice happy medium (and XSI has never complained about the extra legroom heheh)
Are you named after a Skinny Puppy song?
Zbrush can only use 4 gigs, and vanilla 32 bit os can only address 4 gigs. Under vista, the OS gets 512MB of the address space, the app can use the other 3.5 gigs.
Zbrush heavily pages to disk though when operating, so if it is using the full 3.5 gigs, there is no room for a disk cache!
With 8 gigs, you have 4 g for Zbrush, some room for the OS, and the reast can be used as disk cache.
… and a fast hard disk like a raptor and such is apparently a plus…