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XP-64Bit

Posted: Tue Nov 27, 2007 1:53 pm
by Warlock
Ok stupid questing. With XP64 will all my 32bit software will be fine?

Because my MS rep is able to get me 64bit multi lang for 138. Yes I have a 64 cpu

Posted: Tue Nov 27, 2007 3:11 pm
by fliptw
It will.

but do are you using anything that would need access to large amounts of memory?

Posted: Tue Nov 27, 2007 3:12 pm
by Krom
Yeah, 32 bit software still works in XP64, just like 16 bit software still works in 32 bit XP.

Posted: Tue Nov 27, 2007 3:32 pm
by Warlock
Yeah I still do animations and I got 4gb of ram and it sucks only being able to use 3gbs

Posted: Tue Nov 27, 2007 6:34 pm
by fliptw
you'd need a 64-bit app before you can take advantage of the extra memory

running a 32-bit app under xp64 will still leave you with 32-bit limits.

Re:

Posted: Tue Nov 27, 2007 11:29 pm
by heftig
fliptw wrote:you'd need a 64-bit app before you can take advantage of the extra memory

running a 32-bit app under xp64 will still leave you with 32-bit limits.
For every 32-bit process itself, yes. But the system will be able to use the whole 4gb.

Re:

Posted: Wed Nov 28, 2007 1:59 am
by DCrazy
heftig wrote:For every 32-bit process itself, yes. But the system will be able to use the whole 4gb.
Not entirely true. Under 32-bit XP, processes are given 2GB of the address space, the other half is given to the kernel. This prevents thrashing in kernel mode, which is never a good idea. You can use the /3GB switch in boot.ini to change the ratio to 3:1 (same as Linux), and couple it with /PAE to enable Physical Address Extensions (hardware support for 36-bit addressing) to loosen Windows' belt a bit.

Re:

Posted: Wed Nov 28, 2007 10:21 am
by Krom
DCrazy wrote:
heftig wrote:For every 32-bit process itself, yes. But the system will be able to use the whole 4gb.
Not entirely true. Under 32-bit XP, processes are given 2GB of the address space, the other half is given to the kernel. This prevents thrashing in kernel mode, which is never a good idea. You can use the /3GB switch in boot.ini to change the ratio to 3:1 (same as Linux), and couple it with /PAE to enable Physical Address Extensions (hardware support for 36-bit addressing) to loosen Windows' belt a bit.
Correct, but none of that is really a good idea and can often lead to windows crashing. According to anandtech, you can actually set the ratio anywhere you want, but windows gets pretty BSOD happy at anything under 1.3 GB for the kernel.

Posted: Wed Nov 28, 2007 4:22 pm
by DCrazy
The ratio is only configurable for Vista. Everything older can only be set to a 2:2 or 3:1 ratio. PAE is the least likely to cause problems, because pointers are still 32-bit.

Posted: Mon Dec 24, 2007 5:02 pm
by Warlock
just an update iv been running XP-64 for about 6 weeks now and omg its awesome and fast. issues with some software but i expected that.