sirs,
i just bought 4 gb for my windows xp 32 home edition.
i know that this OS just recognizes 3,5, but, in mine, it shows only 2,5 gb
of free memory.
does anybody know, step by step (i am a moron regarding this subject), a way to increase it to 3,5 in the win itself, because i have a 5,000,000 poly object to be finished soon in ZB.
regards.
-
Short answer: Get 64 bit OS. (assuming 64 bit cpu). Even if all the memory were recognized, XP 86 can’t use it…it can only use 2 gb per program without some ill advised registry tweaks.
- Failure to recognize all ram in XP could be from a number of reasons. Older motherboards often wont recognize it…what does it say for your ram in Bios when you start up? Some boards require an option like “4GB remapping” be enabled to recognize all the ram. Some ram is always held back for the operating system and various processes, and ZB wont list it all as “availiable”. If you have an old AGP video card, 64-258 mb of ram will be held back for “aperture caching”.
And then, as you know, XP itself doesn’t seem to recognize it, and even if it did, couldn’t use it. It wasn’t built for a 4 gb world, and neither was a lot of hardware until a couple years ago. Updating your OS should do the trick, but if your MB is old, you might need to upgrade that as well, along with whatever hardware the new board mandates.
note: BTW, even with the ram you have, a 5 million poly object should be no trouble for ZB to handle memory wise in XP 86. On my win xp drive ZB doesn’t get “crashy” for me until I get into that 9-10 million ballpark. If you’re suffering slowdowns with a 5 million poly object, its probably a CPU limitation, not a ram issue.
It’s not ZBrush that is incapable of handling 4 GB of RAM. It’s that 32-bit versions of Windows give no more than 2 GB to any application. So ZBrush COULD use more, but isn’t getting it from the OS.
In 32-bit versions of Windows there is something known as the \3GB Switch that allows Windows to give each app up to 3 GB of RAM. This feature is not supported by Microsoft, however. In other words, it doesn’t work right on all systems, and they know it.
The bottom line is that if you have a 32-bit version of Windows with 4 GB of RAM, you shouldn’t set Compact Mem higher than 2048. Any higher will prevent ZBrush from ever using virtual memory. You can experiment with the \3GB switch, which would let you set Compact Mem up to 1024 higher (for a max of 3072). But if your computer doesn’t work right after doing that, don’t blame us! 
On Windows XP, some drivers, especially VIDEO ADAPTER DRIVERS with onboard RAM, CANNOT run with the /3GB parameter because they require more address space than the 1 GB kernel address space permits.
No free lunch 
markkens, aurick and bingo,
thanks for the answer.
so, my computer is a core 2 quad (2,4), 4 gb ram (667), 8500 gt (512) video card and 250 hd, ASUS P5K SE motherboard.
man, sorry, but where should I see this ram bios? its beyond my comprehension this subject. also, where is this /3GB switch?
can i install ZB in a 64 bit windows?
thanks all.
When your computer is booting, there should be a button, like DEL to press to enter into the computer BIOS.(system setup) It should give you that prompt. See what the Bios is reporting as Ram installed. If you register the full 4 Gig in Bios, but windows doesn’t report having that much installed, the problem is on the OS level. If you don’t see the full amount reported in BIOS, then the issue is first on the motherboard level, and you should see your manufacturers website for information on the subject.