Looking for advice on building a system

My 9 year old computer is finally giving up the ghost, and I'm looking to get a new one that's optimized for use with the latest version of Sonar.  Since I'm not a hard-core gamer, I assume that any system that will run Sonar will run anything else that I would do (which will almost certainly be less demanding of CPU).  So here are my four questions:
 
(1) I'm planning to start with an i7 processor.  Should I expect any significant difference in performance depending on which flavor of i7 I opt for, in particular, will 6 cores (if such a thing exists anywhere outside of Intel's web site) give enough of an improvement in performance over 4 to be worth the additional cost?
 
(2) What motherboard do people recommend (assuming that it actually makes a difference)?
 
(3) Is there any sound card that people like, both for overall quality and for ease of use with Sonar?  In my ancient computer, I have a Creative SoundBlaster Audigy 2 and in the version of Sonar that I'd been running (with an embarassingly small version number), I could never figure out how to get it to use all of the channels of the sound card.
 
(4) Are there any other hardware issues that I should be aware of, and if so, what are they?
 
Thanks for any advice you can give. . .

Thanks for the reply.  How many tracks does the 1010lt support?  I was thinking of getting an ASUS Xonar card, which can process up to 128 independent sounds.  Or does this no longer matter in Sonar?  (I had been using an ancient version, in which the number of independent tracks in your sound file could not, AFAIK, exceed the maximum number of independent sounds that the sound card could support.)

Go to this site to choose your chip http://cpubenchmark.net/high_end_cpus.html
 
They rate the biggest bang for your buck.  When I built mine it was the 2600-K.  K being overclockable style chip.
 
Choose your motherboard wisely due to the fact the PCI sound cards are some of the best (fastest).
However, my Lynx card is PCI not the new PCIe.  So I had to choose a legacy Mother Board that had that slot. 
 
Also, I don't recommend building a mini tower anymore.  My build was a mini tower because it fits in my insulated cabinet by my desk to keep the fans quite (its a ported cabinet for fresh air).  To  hard to find parts like chip cooler fans for overclocking etc....
 
Take a close look at using SSDs.  It's the wave of the future.  Sonar's automatic backup and windows happens so fast- I don't even see it happening at all.
 
Also,  think about a good video card for multi monitors.  Its all in windows 7 now and you don't even need any other software to run them, just the video card driver.
 
Just make sure you start on paper first.  everything has to say that it is for whatever part you are matching.  Chip > Motherboard has chips socket> case fits Motherboard> etc...etc....
 
And like you probably have learned over the years get the most you can afford at the time because the software will keep getting more and more complicated (if history stays on course).
 
I saved pretty good $ building my own but it took a long long time.  When you count  research research, research and ordering with a return,  etc...etc...   ; was it all worth it- yes because now I feel like I know a lot more about computers.
 
P.S.  Oh and be very careful.  For example; did you know that Ram sticks all have to be a matched set?  I didn't. 
 
Hope this helps

Not to sure about using two drives for Anti-virus; due to the fact that the virus could possible move into the other drive (but it sounds like a cheap solution).  You may be ok here,  it just occured to me you could still scan both drives (think about down time for scan though).
What I did was use a older computer for the internet and have VGA and DVI going to one monitor and just switch back and forth (using the monitor's input menu button) between the two computers.   
When your talking about Midi inputs going into the sound card (cable wise) It is just for an instrument/hardware (my Midi keyboard controller has USB into Computer not sound card). 
 
You  don't need any Midi built into the card to run midi files.  Thats a computer language that is within Sonar nothing to do with the sound Card.  Cards do have inputs for Midi and some even have Midi software.  But you don't have to have it with Sonar - As long as your instrument is not Midi out (cable).
 
As far as making music Midi files and importing them into Sonar each with its own channel out to your "Sound Cards Mains" you can do it that way but my lynx card has 8 right and left stereo channels.  I would be limited to that.
 
However, a option may be to Solo each Midi track using Sonar's "Exclusive Solo Mode" with "Solo Override" on the tracks you want to always hear.  When you click on a solo button it shuts the other soloed tracks off automatically.  That way you can hear any Midi track at any given time using just two Main channels (right and left stereo).
 
Got to go run the garbage out to the street for the garbage persons; hope I helped

@Slartabartfast:

I have been using an extremely ancient version of Sonar (3.0 if you must know).  If I want to hear all of the tracks while editing the MIDI file imported from a score-writing program, I have to send each track to a separate input channel of the sound card (a Soundblaster Audigy).  I had assumed that modern versions of Sonar worked the same way.

@slartabartfast:

I agree that at least some of the limitations seem to have been from the sound card.  I don't want to spend gazillions on a sound card (I just use the computer for creating sound files -- if I want to listen to music, I use what in the olden days was called a hi-fi -- and I don't plan to use it to record live music), which is why I was wondering if something like a Xonar Essence STX would be sufficient for my needs.

@slartibartfast:

> If you do not understand how to play multiple tracks simultaneously in Sonar 3,

As Marge Gunderson says, you have no call to get snippy with me.  Of course I know how to *play* multiple tracks simultaneously in Sonar 3 -- the main reason for my wanting an upgraded computer is that if I play more than a couple at a time, the CPU crashes, and no amount of fiddling with latencies and buffers or stopping other programs (e.g. antivirus) that might prevent SONAR from using its fair share of the CPU seems to help.  (IOW, despite all appearances to the contrary, I am in fact not a moron -- just someone who is about a decade behind the times.)

> What are you using to turn your midi file into audio data? Are you using the
> soundblaster synthesizer or a soft synth, sampler or rompler?

I generally use Garritan Personal Orchestra for solo instruments and Edirol for section strings and percussion.

>  In your case the answer is in the computer and specifically in Sonar 3. When do they
> get mixed? Before the stereo signal is sent to the sound card. Believe me it is possible to
> play many tracks simultaneously through your sondblaster if you have your sonar tracks
> set up correctly.

Yes, and I manage to do that successfully.  But at least the way my old computer is set up, I have to assign each one of the Sonar tracks to a MIDI I/O channel of the sound card.  I suppose that could have been a mistake on the part of the people who sold me the computer, but that's the way it is -- the only option for MIDI device that I have (at least the only one that actually leads to a sound coming out of the speakers) is the Soundblaster. 

> Signal flow in Sonar is a lot simpler and logical than music notation, but you do need to
> spend some time understanding how it works.

Which is kind of the whole point of my initial query:  since it's been nearly a decade since I bought a computer, I was under the (possibly mistaken) impression that improvements in Sonar and possibly in hardware (e.g. the sound card) and operating system (Windows 7.0 vs. XP) may have made it possible to create a signal flow that is simpler and more logical than it was at the time that I got my previous computer.  Before I invest the money in a new computer (and in an updated version of Sonar), I am trying to figure out what system I can design that will best meet my needs.

If you tell me that the treatment of the MIDI signals no longer needs the involvement of the sound card, then I can accept that.  If you tell me that it never did and that I was misled by an incorrect setup of my computer into thinking that all MIDI I/O had to go via the sound card, I can accept that as well (although I remember being told at the time that sound cards that lacked MIDI I/O were less user-friendly for music editing than Soundblaster cards were). 

If all I need to know is that for editing a MIDI file produced by a notation program like Sibelius or Finale, the sound card doesn't matter, and that I will find that any sound card equally compatible with and equally easy to use with Sonar, then that's all that you have to tell me without putting on airs about your superior knowledge.  The issue then becomes which sound card is most compatible with Sibelius.  The people at Sibelius claim that the ASUS ASIO drivers don't work, and that an ASUS sound card will cause Sibelius to crash.  I have been unable to get independent confirmation for that claim -- it might be true, but on the other hand, M-Audio and Sibelius are both sold by Avid, so the people at Sibelius certainly have an interest in convincing me not to buy an ASUS sound card.

I apologize for underestimating your abilities balock63. Sometimes in trying to be helpful, without knowing who is at the other end, I make incorrect assumptions. You are not the first to note that the tone of my advice sometimes seems like putting on airs--some would say self-aggrandizing supercilious condescension is more apt. I was not trying to be deliberately insulting. 
 
I was, and remain, confused about the original idea that a sound card with more independant channels would help with your problem. A better sound card might be useful in a lot of ways, but the sound card is probably not at the root of your performance problems.
 
If you are having overloads/dropouts while attempting to play a lot of tracks through your main out bus, then a better processor/motherboard would help. Even more important than a processor upgrade for someone who is using a lot of memory-resident samples, would be more addressable memory. That means you need to run a 64-bit Windows system. Windows 7 -64 would be the most reliable system for that. You can get access to 16 GB with the Home Premium version. That should be more than enough. Although the Professional version will address 192 GB of memory, there is no motherboard made that will accomodate that much.
 
 

I am hoping that a 64-bit Windows system with an i7-3930K processor and 32 GB of RAM will solve at least some of my problems -- I've been warned that even that may not be enough to have an "orchestra" running without crashing the system

This is exactly what I'm running (see sig)

I recently finished building my orchestral template based around EWQLSO Platinum Plus.
The template consists of about 7/8 instances of the Play Engine and I have loaded up more articulations than I probably need, and so far ir barely tickles my cpu, RAM is reporting 7.7Gb

I have yet to actually compose anything, though I don't foresee any problems.

A couple of years ago, it would have been necessary for this scenario to require multiple computers running different parts of the libraries, but not any more.