I am thinking of upgrading to Win 7 and X3 from 8.3.5 Producer which is on on my old P4 XP Pro Box.
I have another computer which I am replacing tomorrow for office work with a Dell Intel i5. The old office box is a Antec Sonata case with Asus MoBo and an Intel Core 2 duo at 2.2 gigs processor speed, I can update the RAM for 64 bit X3 use to whatever it will run and as needed.
 
If that processor is not good enough for X3 I will just install an unused copy of XP Pro I still have and work it for audio use.
 
Thanks

System Requirements X3

Minimum system requirements

Windows 7 or Windows 8 (32 and 64-bit). XP and Vista are no longer officially supported.

Intel Core 2 Duo E8200 2.67 GHz / AMD Phenom Quad Core 9750 2.4 Ghz or higher

2GB of RAM

Harvey,
I am running Win 7 Pro x 64 , E8400 @ 3Mhz / 6GB DDR2-800 with Sonar X3e producer x64. I also have an ATI HD6450 video card running 3 monitors. I use the Aero theme (plain jane settings) in Win 7 to push the video tasks out to the GPU.
First, Sonar X3 does take more horsepower than 8.5.3 but not that much.
I also have Sonar X3E Producer x32 installed along with x64 but I am not sure x32 makes that much difference performance wise. I have not tested this thoroughly however.
Whether your setup works for you depends largely on what you use it for. If your projects are primarily audio with some backing synths, you are probably good with that setup. Do not expect to run 25 instances of Dim Pro or a lot of linear phase plugins @ 96/24 though.
Sample rate really matters. I usually work at 48Khz/24 bits although 96/24 works well for mostly audio projects even with 20 or more tracks. In a typical project I will have 2 or 3 Dim Pro instances, Addictive Drums or Session Drummer 3, SI-bass, and maybe one or two other synths along with 4 or 5 audio tracks... without freezing tracks, my CPU meter will be about 40-50%. My buffers are 128-512 @ 48 Khz usually but I can get my interface down to 32 if I am simply recording a couple of audio tracks.
If you do heavy synth projects, you may have to freeze some synth tracks.  
THe usual DAW performance things help a lot with an underpowered system...separate HD for samples and so on.
Sounds like this is a secondary DAW system. For me it is my primary DAW so I am thinking of new one. I just got an I7 laptop running win 8.1 with an SSD that rocks and I  use that for guitar synths and TH2/guitar rig but I Ilike the 3 monitors (which the laptop will not do) so an upgrade from the E8400 will probably happen this year. 
I like to keep my old systems and rotate them to different functions. THe E8400 will replace my current Celeron file server while the Celeron goes in the dumper and so on.
My advice would be to try it. I am sure you could still get some use out of it
Hope this helps.
Michael
 

Harvey,
Another thought. In the last week I have been experimenting with using my laptop as essentially a midi-guitar synth computer. I set the laptop up for this so I can take it on the road. Although I have synths on the laptop for gigs, I tried connecting it's guitar to midi to the main DAW running sonar using rtpMIDI and controlling Sonar synths with it. rtpMIDI sets up  midi connections over ethernet and allows me to drive Sonar synths with the midi-guitar outputs. This works really well with ~1ms midi latency over a 100Mb ethernet/54Mb wifi.
I was thinking of upgrading the main DAW to Core2 I7 and using the E8400 as strictly a sample player computer. On the E8400, install heavy sample players like Kontakt, Sampletank,etc and send midi to these over rtpMIDI from Sonar then bring back the sample player audio via the DAW's audio interface into Sonar. Remote Desktop (or VNC) the E8400 and the sample player GUI's could be controlled from the DAW computer without the E8400 needing kbd, mouse or video monitors.
Just a thought.
Michael
 

Thanks microapp, great responses with good advice, here is how I record. I do synths, and samples into Sonar using MIDI with a MIDI keyboard controller, or a composition program for the backing tracks. I immediately render each track to audio with only 2 or 3 sample players at most. I also have a synth in my computer and that is hardware so only the MIDI track is using any CPU.
 
Once the BT is done, I will then play live guitar in and vocals, either one first. I don't do videos (not yet) This will be my primary DAW, with the P4/8.5.1 producer as a secondary backup unit. Of course I will optimize the DAW and Windows for audio production, and keep my app loading down to a minimum. I have not built a new DAW since 2003 since the P4 has worked almost perfectly all that time. Once I get 7/X3 tweaked. And I like it, I can throw a new Mobo/CPU/RAM together in the Sonata 2 case to optimize performance if needed using the same hard drives.
 
Thanks for taking the time to comment.

Harvey,
From your workflow description, it sounds like you can use X3 on the E8400 without too many issues. Your workflow is similar to mine except for the h/w synth. Good luck !
 
Michael

me. on Sonar x2. it”s working...

me. on Sonar x2. it”s working...

Working for me, though I'm not really pushing it.

Thanks I will go for it.....

Harvey: Asus MoBo and an Intel Core 2 duo at 2.2 gigs......tell me the exact model of the motherboard !