I have XP Pro 32 and 64 bit partitioned.
Both Poser 6 and 7 will run in the 64 bit mode but will not take advatage of the 64 bit system.(They will still run in 32bit) however Poser will take advantage of the Dual Core system.
E frontier have told me that they are looking at a 64 bit render engine for P7.
Adobe Photoshop CS2 has a 32 and 64 bit operating system.They will run in both.
I do not have  Carrara or Z brush but I assume they will run in the 64 bit mode but unless they have a 64bit program they will only run in 32bit.
This is my experience with both operating systems.Just make sure if you are running a 64 bit system you get a good video card and update  the drivers.
I am running a Nvidia 7600 GS TDH.
My system is a Tyan motherboard, with dual AMD Opteron (TM) 248 Processors 2.19 GHz and 4 gigs ram. Hope this helps.Cheers

Custom built computer 128 gigs RAM,4 Terabyte hard drive, NVIDIA RTX 4060 TI 16 GIG Gig,12 TH Generation Intel i9, Dual LG Screens, 0/S Windows 11, networked to a Special 12th Generation intel I9, RTX 3060 12 Gig, Windows 11,64 gigs RAM, Dual Phillips Screens, 2 Terabyte SSD Hard Drive plus 1 Terabyte Hard Drive,3rd Computer intel i7,128 gigs ram, Graphics Card NVIDIA RTX 3060 Gig,1 Terabyte Hard Drive, OS Windows 11 64 Bit Dual Samsung Syncmaster 226bw Screens.Plus INFINITY Laptop 64 Bit,64 gigs RAM.Intel i9 chip.Windows 11 Pro and Ultimate. 4 x 2 Terrabyte Hard Drives and 2 x 2 Terrabyte external USB Hard drives. All Posers from 4 to Poser 2010 and 2012, 2014. Poser 11 and 12, 13, Hexagon 2.5 64 Bit, Carrara 8.5 Pro 64 bit, Adobe Photoshop CS4 Creative Production Suite. Adobe Photoshop CC 2024, Vue 10 and 10.5 Infinite Vue 11 14.5 Infinite plus Vue 15 and 16 Infinite, Vue 2023 and 2024, Plant Catologue, DAZ Studio 4.23, iClone 7 with 3DXchange and Character Creator 3, Nikon D3 Camera with several lenses.  Nikon Z 6 ii and Z5. 180-600mm lens, 24-70 mm lens with adapter.Just added 2x 2 Terrabyte portable hard drives.