Dual-Boot- Winxp Pro/ win7-64 or Win7-64 only?

[europanorama]

I have setup this MB by Asrock(could get it really cheap)
http://www.asrock.com/mb/NVIDIA/ALiv...Download&os=XP

Will upgrade to 4x 2gb DDR2(same chips). dont know yet which processor inside. it has AM3+-option.

Want to use win7-64 for the first time. someone meant its not easy when having no experience. but i ahve 18 years of pc-knowledge. Ok, always some years behind....
Thats why i opt for a Dual-boot on a 500 gb-drive SATA2.
120gb SSD is another option. would get it anyway later for a second installation.
How big should be the systempartion? or must there be two?
For winxp only i think 34gb would do. But i dont want to use winxp-if possible- anymore.
for win7-64. 50 or 100gb?
What do you think?

[Train]

I recommend a minimum 120 GB for Win 7. 100 should work.
4 GB or ram.

The top cpu for that board is a
AMD Phenom II X4 965 Black Edition
Which would be more than enough.
CPU listings.
http://www.asrock.com/mb/NVIDIA/ALiv...SATA2/?cat=CPU

Seems like a good mobo to me.

Gave Win 7 a 2 week trial and have not reinstalled xp because all programs are running fine.
But I have ultimate so I could go this route if I needed XP.
http://www.microsoft.com/windows/vir.../download.aspx

But remember

Windows XP Mode comes as a separate download and works only with Windows 7 Professional, Ultimate, and Enterprise. Windows XP Mode also requires virtualization software such as Windows Virtual PC. Both are available free on the Microsoft website.

http://windows.microsoft.com/en-US/w...indows-xp-mode

[europanorama]

I will leave like it is, no more upgrades. Next much better PC will coming soon:
http://www.ebay.de/itm/Aufrust-Bundl...item484f432365

[europanorama]

The slowest processor in the list is installed.....
Sempron 3000+(64bit) 1600 Mhz-256kb cache
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Winxp- system/program-partition was 34gb until know. should i use 50gb if i will add video and photoprograms?
Actual system:from 34gb 19 are free. but no special programs installed-pc too slow. 8 years old amd xp+