The DPCLAT will show issues pretty much right away, What you can do is let it run for 5-15 minutes. Any processes that were lurking will show up by then. 

Hmm an hour , that's a different kettle of fish. As Daveny is warning you'll hit the file size limitation.  
I would see if there was any point in the show that you could spare 30 seconds it would take to hit save. The fastest way would be to close the project window via the red X. It will ask you if you want to save.  Then start a new recording with one of the already open files like I mentioned. You could have multiple projects open and layered over top one another.   
If Sonar crashes you'll loss everything so you have to figure a way to do a few saves or the whole thing is gone. Tell the band to have a smoke after the 5th song. Sets of 4 to 6 songs would be ideal. 
Just remember, the longer the song , the longer it will take to save, This is where a faster CPU would help. 
You'll find that when you hit the space bar to stop that the waveforms will take forever to be drawn too, don't worry, it's not important to the recording. 
 
I've been told that if your hard drive is full then the wave file cnnot fit in one space so there is an interuption while the hard drive looks for the next space. This is why I would only attempt what your doing with a fast and empty hard drive, Might be better to use an external drive, long as that old turkey has USB 2. 

Cactus Music


The DPCLAT will show issues pretty much right away, What you can do is let it run for 5-15 minutes. Any processes that were lurking will show up by then. 

Hmm an hour , that's a different kettle of fish. As Daveny is warning you'll hit the file size limitation.  
I would see if there was any point in the show that you could spare 30 seconds it would take to hit save. The fastest way would be to close the project window via the red X. It will ask you if you want to save.  Then start a new recording with one of the already open files like I mentioned. You could have multiple projects open and layered over top one another.   
If Sonar crashes you'll loss everything so you have to figure a way to do a few saves or the whole thing is gone. Tell the band to have a smoke after the 5th song. Sets of 4 to 6 songs would be ideal. 
Just remember, the longer the song , the longer it will take to save, This is where a faster CPU would help. 
You'll find that when you hit the space bar to stop that the waveforms will take forever to be drawn too, don't worry, it's not important to the recording. 

I've been told that if your hard drive is full then the wave file cnnot fit in one space so there is an interuption while the hard drive looks for the next space. This is why I would only attempt what your doing with a fast and empty hard drive, Might be better to use an external drive, long as that old turkey has USB 2. 

Thanks again Cactus,
I ran the DPCLAT on my laptop when I was home for lunch for may be 15 minutes and it was all nice and green. Although I was not working the lap top hard. I checked a few things on the Windows event viewer, few copy/paste files (small ones) and that s about it.
I ll let it run for a while tonight to make sure
 
I wasnt aware about the file limitation... I had to check on it really fast and I didnt find much. I found a post in this forum, about the 2 GB size limit of the bundle files which has been fixed after the 8 version, but I am not sure if that is what we are talking about here... So the question here is if a session can be 2GB in size or more?
 
The truth is that although I ve been using Sonar since the 2 XL times, I ve never really used it for field recordings. I mostly use it for MIDI and Mixing.  Alesis HD24 was my recorder of choice but now it s gone and I am losing my mind!
 
I will try to get the lap top right next to me but that s going to be hard, so I am mostly concerned about "Plan B" where I wont have access to the lap top whenever I can.
 
I will start making templates tonight and start practicing.
 
Thanks again!! I ll keep you updated

Some updates

about DPCLatency
Left it running for about half an hour and everything is nice and green. I would say better than my desktop.

I have been recording for about 10 minutes now 8 mono tracks and no hick ups so far.

@Dave
the CPU meter in SONAR is showing 01-02%
The Disk meter in SONAR is showing between 02-05% 

I ve just opened the task manager and CPU is showing 100%
I think I am going to have to pack some ice! lol. 

what bothers me is that in the audio preferences in SONAR the 24bit is grayed out and I cant find the setting in Scarlett mixer options to change it to 16bit

It s going to be a long night... 

You should be able to change that setting in the Scarlett ASIO panel. 

What I notice is that in ASIO mode that is greyed out, If you change it to WDM it gives me options from 16 to 24. But I set mine in the Tascam control panel. 

Cactus Music


You should be able to change that setting in the Scarlett ASIO panel. 

What I notice is that in ASIO mode that is greyed out, If you change it to WDM it gives me options from 16 to 24. But I set mine in the Tascam control panel. 

Thanks for your reply,
 
Well.... I know it should change from the ASIO panel but unfortunately there is no option, or at least that I can find right now.
 
Coming from EMU 1820 with an amazing virtual router/mixer UI, this Scarlett's mixer looks like a cheap plastic toy.
 
Anyways, I dont think there is an option to record in a lower bit rate... If anyone has any information about how to lower the bit rate in ASIO I will be so thankful
 
I found this in the Focusrite site.
 
"This article addresses concerns raised by some about 16 bit and 24 bit in Windows systems.
When using the WDM driver, only 16 bit modes are seen as an option in the Advanced section of the interface's Properties. However, this setting has absolutely no effect when recording using the ASIO driver, which users should always use in DAWs, due it's its low latency and increased peformance over WDM (Windows' own audio driver).
The audio stream captured from our USB 2.0 hardware is always 24-bit samples. These samples are not altered or processed in any way by the driver when recording via the ASIO driver. Windows audio control panel may say the device is in 16 bit mode, but the ASIO driver bypasses the Windows audio system, and is therefore not affected by this setting.
Therefore, using 24 bit depth in your recording software, while using the ASIO driver, is still 24 bit when recording/creating, where 24 bit actually matters.
 
http://www.focusrite.com/answerbase/en/article.php?id=1209
 
Now the problem is, how to deal with the CPU load...
Although it seems like the laptop is behaving fine I am concerned about the temperatures.
The highest buffer size I can select in the Scarlett ASIO panel is 20 ms.
 
Does the Read/Write Cashing play a role in lowering the CPU load?
 
Have a nice day everyone!

From what I understand, the Sonar CPU meter only shows Sonars CPU usage, If the Task Manager is showing a higher reading then theoretically it is not Sonar but some other process causing this. 

If I get a change later I'll hook my laptop up and try a test , I never opened Task Manager while running Sonar so might have been oblivious to this. I do have a better CPU than yours, but my old 2004 Acer was same specs as yours and it recorded fine.  

I have only 21 processes running after some house work in msconfig, I assumed you did the same as you said you set the laptop for audio. But I don't think those make much difference. 

The process SONARSTD.EXE uses 94-99% of the CPU just by starting Sonar.
But even when I record the load doesnt change.
I dont like the Task Manager in Windows, I dont use it because it s kind of problematic.
I never noticed how Sonar loads the CPU.  
 
Anyways I have no Plan B, I have to use this laptop for the session and if it makes it I will be happy, if not... let that be a lesson. 

Not much to add to the good advice Cactus has been giving you except to make sure that if your laptop has a built-in wireless network adapter, it's disabled prior to recording.

It's also probably not a bad idea to defrag your hard drive in advance to maximize the amount of contiguous disk space available while you're recording.

If possible have someone sit at the computer during the recording so they can spot problems as they occur, such as clipping from a channel's gain being set too high, or loss of a channel because a microphone cable has come loose. Have them stop recording between songs and do a save, then start the recording back up.

That's odd about your Task Manager. I just tried it on 2 different computers and they both are showing a low reading with a song playing, This one is a few audio tracks and MIDI via TTs1. Both computers are XP P4 and 1.5 GIG RAM 2.5 Mz. single core. This screen shot is from my office computer and it's so full of apps and software, It is not optimized at all.  The CPU usage history shows it was high during Sonar loading then it settled down to 5-15% 

@ Cactus
Thanks again for following up,

Yeah, I am not sure what s going on. It seems like Sonar is taking over the CPU for itself. I dont really mind but I ll check to see what s the case on my desktop.

Something that is even more odd... I just recorded 8 test tracks and looked at their info at the Sonar Audio Folder and the files were 44KHz/16bit. Which of course is what I wanted... So the official explanation of Focusrite about recording 24bit on ASIO is nonsense or I am missing something here.

@bit
Thanks for your advice,
I dont use the wireless adapter anyways and it s always off.
The drives are checked for errors defragmented and they are good to go.

Unfortunatelly I wont have anyone to help me with the recording. I ll have to do everything by myself.
Start-Stop-Save-Start probably will be the way to go I just need to find a way to have the laptop close to me.

Does anyone know if long USB cables have any effect to the recording?

Thanks again everyone you ve been so helpful!