Thanks,
so do I run the X3 download again and just choose 64 bit, and run both versions on my Laptop, how much extra HDD space will it take if I reload it and all/ most / some of my 3rd Party Plugins? P.S. Yes 64bit Windows, I have 8gigs of RAM, so, as I am using 32bit Sonar on 64bit Windows does that mean that I have NOT been accessing my 8gigs, but only 4???

Once you get use to 64 bits you will not want to use 32 bit plugins. There will be a transition time as you decide to forgo non 64 bit plugins because 64 bit ones seem happier in a 64 bit host.   
 
None the less most 32 bit plugins will work just fine in  Sonar 64 bit. DX 32 bit plugins wont. 

Thanks,
so do I run the X3 download again and just choose 64 bit, and run both versions on my Laptop, how much extra HDD space will it take if I reload it and all/ most / some of my 3rd Party Plugins? P.S. Yes 64bit Windows, I have 8gigs of RAM, so, as I am using 32bit Sonar on 64bit Windows does that mean that I have NOT been accessing my 8 gigs, but only 4???

Yes, that is how to install 64bit SONAR. The best way to estimate the disk required is add up the current 32bit installation. Make sure not to include the sample libraries for synths such as DimPro, Rapture, Session Drummer and Loops and One Shots, they are shared between the 32bit and 64bit versions. Yes, a 32bit application will only address something less than 4GB of RAM regardless of how much is installed.

The only way you can get around the 4GM RAM limit in 32-bit Sonar is if you ReWire another DAW into it. Using this method, you can host some of your VSTi's in something like Reaper and ReWire the audio back into Sonar. I used to do this with ProTools and Reaper. I'd host a bunch of synths in Reaper. Then ReWire the MIDI from ProTools into the Reaper synths, then ReWire the resultant audio from Reaper back into ProTools. Took me a while to get my head around it and set it up but once it was up and running it worked perfectly, and I was able to use a lot more synths. Previously, ProTools had been crashing a lot because of the lack of memory available. The only drawback was having to load both DAW's in a particular order, then close them in a particular order. It was great to switch to 64-bit Sonar and use all of my RAM. 

Some 32 bit vst just don't play nice in my X1/X2 64bit. I have much less problem in X3 64bit thank goodness. You have to try which one 32bit vst works in X3 64bit. The 32 bit vst will be bridged into 64 bit Sonar by bitbridge. Recently Cakewalk bought over the rights to bitbridge and I guess Cakewalk might have done something to make bitbridge more stable. (I am just guessing that because X3 now is a lot more happier working with my 32bit vst).
 
I still prefer to use 64 bit vst exclusively in 64 bit Sonar because the use of bitbridge would cause more delay/latency. When I have to use sampletank and miroslav(both only in 32bit) i would use the 32bit Sonar X3.

I use lots of 32bit plugs with minimal issues. 64bit Sonar is a MASSIVE improvement performance-wise. Provided you're running Windows 64bit of course..

Thanks again guys.
Do any of you have a list of known Soft Synths and Plugins/Brands, that are inappropriate/problematic in 64 bit Sonar.  And I presume that the term 'Running Windows 64bit' means that the OS itself is 64 bit? 
Also, what Third Party Synths and Plugins do I not need to install again in 64 Bit Sonar, or do I have to install all again?

Thanks again guys.
Do any of you have a list of known Soft Synths and Plugins/Brands, that are inappropriate/problematic in 64 bit Sonar.  And I presume that the term 'Running Windows 64bit' means that the OS itself is 64 bit? 
Also, what Third Party Synths and Plugins do I not need to install again in 64 Bit Sonar, or do I have to install all again?

Thanks again guys.
Do any of you have a list of known Soft Synths and Plugins/Brands, that are inappropriate/problematic in 64 bit Sonar.  And I presume that the term 'Running Windows 64bit' means that the OS itself is 64 bit? 
Also, what Third Party Synths and Plugins do I not need to install again in 64 Bit Sonar, or do I have to install all again?