What about HDD controllers?,,,I was having issues like this aswell , my motherboards HDD controller was a MLC micron chip...and it seems to have problems which may be causing my issues with playback with SSD and HDD streaming in Sonar 1x ,2x, 3x...
Unfortunately the MLC micron controller firmware is out dated and cannot be flashed on my Board...So I had to change the MB board....and that is still being built, due to issues with new power supply toasting my new boards.
 
Technology....isn't it wonderful?
 
Not saying this is your problem...What Motherboard and controller is on that system?.
 
I would start by turning off redundant onboard devices in the Bios...example onboard sound, firewire, wi fi, and internet nic...if you got em.
And give that a whirl... 

Check the drivers. I have always had better results using ASIO. Multimedia and WDM drivers have never worked well on any of my rigs.

@guigz:
You wrote:
The fact that sonar indicates 2.8Gb ram usage is just normal. It displays the ram it uses and not ram available.
 
Agreed, but the ram it uses could be also the ram available.
Often my elder 32 bit systems show 2,6- 2.8 gb ram used by sonar.
 
I still recommend to try out a real audio-interface.
To run sonar with an onboard chip is compareable  
driving a porsche targa 911 on 13 inch wheels.
 
Another matter could be that you have installed Sonar as 32 bit version.
 
Have fun
Pragi
 
 
 

It sounds like the Realtek is just your "windows sound card".  But just as a check of things, in Sonar, do you load the Realtek card as any part of the equation?  If so, dump it from the Sonar config.  It could be that the ART is fine and the Realtek is bumming things up.  In the Audio Preferences, I'd remove (or make sure it's removed) the Realtek and see if you still have those issues (restart Sonar for good measure even though you probably don't have to).  I'd also try both WDM and ASIO and pretty much avoid MME for anything.
 
Generally, these onboard cards are not designed to work well in this regard.  Granted, I haven't tried such a thing in years and maybe it has improved since, but they are pretty much least-common-denominator.
 
Hope that adds something.

 
@Blades,
The arte device is not a soundcard/interface, it´s an USB-Pre-Amp.

grizwalter
 
Finally, my computer isn't the worlds fastest, but it is in good shape and I was able to run MC6, MC6T, Sonar X3 (the basic one) and Reaper all without any of this level of problem. I've mixed more than 60 tracks on Reaper and Sonar X3, and the only thing in the current tune is the number of tracks--no midi or other such things. I realize the processing of prochannels and such is more intensive perhaps, but I've also more than doubled my RAM.
 

Has anything changed in how projects are created between the other DAWs, the 60 track project and this project. Were they all using the same sample rate? You mention ProChannel use, what other plug-ins are in this project?

1. As pointed out, RAM just isn't going to make the big difference you expect it to. Even with larger buffers. It will help with streaming tracks from the disk, and when dealing with large sample libraries, but this isn't where most of your CPU goes in the first place. 
 
2. Plugins eat up the most CPU and are the most likely culprit. If you're running lots of EQs, compressors, reverbs, pro-channel modules, you can easily eat up all of your CPU on a 44 track project. I can easily bring my i7 to it's knees on a 15 track project if I wanted to.  Your options are, 1) use fewer plugins, 2) use less CPU intensive plugins, 3) be clever about how to use fewer plugins (for instance bussing), 4) get an external DSP card like a UAD for extra juice, then buy some of their plugins, 5) upgrade your CPU. The faster CPU's get, developers will take more and more advantage of the extra processing cycles, so as your CPU speed increases, your track count might stay the same based on which plugins you use.
 
3. Last point: sometimes you'll have to increase latency/buffers just to deal with plugins that introduce large amounts of latency. For instance, SKNote's Verbtone crackles and pops with low latency, and always requires larger buffers.

Funkybot
 
 4) get an external DSP card like a UAD for extra juice, then buy some of their plugins, 5) upgrade your CPU.

Well, If you can afford an UAD with the plugins, you'd better change your CPU/Mainboard. You can upgrade both for something like 200euros (The price for 1 UAD plugin)
 
Also try ASIO4ALL..You may get good surprises (ok,it's better to have a real audio interface with dedicated ASIO drivers)

Wow, tons of stuff to go over there.
 
First of all, a couple people said that my A.R.T. Dual Pre unit is not an audio interface. That is incorrect. It is a preamplifier AND a Computer Audio Interface. I've had no problems with it whatsoever at any point previously, so let's take that out of the equation.
 
2nd thing a couple people asked is about my Windows version. It is, without a doubt, Windows 64-bit. Also, for the record, Windows 32-bit can only handle 4 GB of RAM, but my system shows that it has 7Gig to use. I did wonder, however, about that 2.6G (approximately) mark X3 is showing me in usage; that is the exact same number it was showing me when I was running with only 3 Gb of RAM. It is almost as if Sonar X3 doesn't realize I have the 7 Gb available or something.
 
Let's see, what else? I am not loading my Realtek at all; in fact, I have disabled all my sound options except for my USB CODEC which is the interface.
 
It was noted that using 7 Gb of RAM was odd as well, and I tend to agree. However, I've tried things using 6 Gb (three 2 Gb cards inserted) as well, and no change in any way.
 
To my mind, this is coming down to the unfortunate possible reality that what many people here have indicated is correct: RAM doesn't matter much. I find that incredibly hard to swallow and, frankly, disappointing. If RAM isn't at play, then what is the point of Read/Write Caching at all? It seems to me that system intensive programs would go out of their way to utilize the resources available to help run things smoothly. A lot of people asked about the plug-ins involved, but like any 44 track mix, one can assume there are going to be a lot of them, and of course I understand they bear down on the system. However, that doesn't change the fact that upping the RAM SHOULD have helped a lot (considering more than doubling what I had), and instead it did absolutely nothing. And as one person noted, the 2.6 Gb usage shown by X3 is just that--its usage. So when I had 3 Gb of RAM, it showed me the exact same number, meaning either it doesn't know I've added RAM, or it simply refuses to call upon it as a resource.
 
I'm pretty much stuck until someone can tell me how to get it to use the RAM I've got! I'll also be looking at the CPU upgrade prices. In this regard, I'm a complete computer idiot.

All you have determined is that the project is not memory bound, which has been suggested in both threads (I am guessing this is a continuation of the other thread about a "44 track project"). The cache setting in SONAR designed to make up for older HD controllers and has practically nothing to do with RAM usage. Unless your RAM can translate into more CPU and I/O thoughput (which it cannot) the project is dead. While track count is not particularly meaningful, was the "60 Track" project mentioned before recorded at the sample rate and bit depth? FWIW, extreme latency and I/O settings (mentioned in the OP) can degrade performance to the point that a project will not track.