A little advice on upgrading from 8.5?

I'm hoping I can get a little guidance here.  It's been a few years since I actively used Sonar, and am looking to get back into DAW recording.  The last version of Sonar I used was 8.5, but I am very intrigued by all the features of X3.  Before I make the upgrade (which will also require me to upgrade my computer's OS), I wanted to check on some things here.
 
I use a Dell Optiplex 755, with a 2.4ghz processor, 8gb ram, and 2 500gb Maxtor hard drives.  I currently run XP, but I know I need to upgrade to at least Windows 7.  I guess my first question is:  Is the 2.4ghz processor powerful enough for X3?  That is the minimum requirement I could find for processor speed, but my 8gb ram is 4x the minimum for memory.  I am also wondering about 32 vs 64 bit.  Should I buy a particular version of Windows 7?  Are the 32 and 64 bit versions of Windows 7 sold as different packages?  I'm assuming they are.  And, depending on whether I have 32 or 64 bit Windows, do I then need to download the corresponding upgrade of X3?  Are there different 32 and 64 bit downloads of X3?
 
If there are any other potential issues I should be aware of before I start the whole upgrade process, I wouldn't mind having them brought to my attention here!  Thanks a lot for all who contribute to this forum; it was definitely a contributing factor when I decided to go with Sonar as my DAW of choice.

Before spending any money on the PC run the X2 demo on it. Then you can see if the hardware is adequate for your needs. IIRC, the X2 demo does install on XP.
 
Using 32bit Windows defeats the purpose of having 8GB of RAM because only 3.5GB would be used. Install 64bit Windows.
 
SONAR includes both 32 and 64bit versions in one installer. Assuming you are moving from 8.5 32bit, you would probably want to install 8.5 32bit and both 32 and 64bit versions of X3. They all will run fine on 64bit Windows. This will help opening older projects and transitioning to 64bit.
 
 

The machine appears to be 5 years old?
Factor in your budget the cost of windows 7/8 vs the cost of buying a new machine with windows 8 (assuming you haven't already bought the OS).
 
Cheers..

Well, it appears that Dell does not "officially" support Windows 7 for the Optiplex 755.  However, a cursory Google search reveals that it does tend to work, and even Dell says that one can oftentimes use Vista 64 bit drivers with success.  I think I'll gamble the $100 or so (I'm assuming that Home Edition is okay for single-user music production) and hope that it'll work, as that's quite a bit cheaper than buying a new computer with specs suitable for this type of music production.  With any luck, I'll be back soon asking more Sonar-specific questions.  I just need to wade through these OS installation issues before I even get to Sonar X3.  Thanks for the help!

Interesting, I didn't know that.  I know that OEM stands for "original equipment manufacturer", but my plan was to go to Best Buy and just grab a copy of Window 7 Home (after hopefully verifying that it has the 64 bit version).  So I assume that by getting it at a retailer, it would be a retail copy?  Or could I inadvertently purchase an OEM copy at a place like Best Buy?  Sorry if I'm straying a little off-topic; this is all designed to get me running X3, I swear!

Please also be reminded of scook's post #3 - if you install 32 bit Windows, your system will only see approx 3.25Gb of your installed RAM.
 
The remainder will sit there doing nothing.

Update:  With the price of a retail version of Windows 7 being over $200, and with my PC being 5 years old, I starting leaning toward just buying a new system with Windows 7 pre-installed.  Then I found that I could get 24 month no-interest financing from Sweetwater, and that they sell custom-built systems optimized for audio.  So next week sometime, I should be getting my new system, and can then finally start working with X3.  The specs are as follows:  Intel Haswell Core i5 Quad 3.4Ghz, 4GB RAM, 2x 1TB HD, Windows 7 Home Premium 64 bit.
 
I know 4 GB RAM is pretty slim, so I think as soon as it's delivered I'll add another 4 GB.  The other drawback to the system is there's no Firewire port; it's all USB.  My current audio interface is Firewire, so I ordered the Focusrite Scarlett 2i2 USB interface for use with the new system.  As 2 simultaneous inputs is the most I ever record at one time, I'm not too worried about the whole USB vs. Firewire issue.
 
As someone who primarily uses synth and drum plug-ins, with the only live instruments being guitars and vocals, I think this setup should serve me pretty well.  Yes, I could have taken the time to build a comparable system for less money, but that's a little out of my comfort zone, and I mentioned the no interest financing!  I'd welcome any thoughts or words of advice/caution about this system and how it should handle running Sonar X3.  Thanks to all!

Well, it's already ordered with Windows 7 64 bit, so nothing I can really do now.  Everything I've read indicates that it's a very good OS for DAW work.  With the general uproar over Windows 8 when it came out, I thought that going with 7 was a wise choice.  I know 8.1 was supposed to have helped a lot.  Are you happy with Windows 8.1?  And do you see a big advantage in using that over 7?