gwen,
I just re-read this thread and you have not said much about your PC(s).
Could you describe the windows versions , processor chips, speeds, memory and disks you are using.
Disk access time is particularly important while recording.
In the device manager look at the ATA controller settings and make sure your HDD is using DMA ultra mode-whatever and NOT PIO mode.
 
Here is how to check that
http://windows.microsoft.com/en-us/windows/turn-direct-memory-access-on-off?woldogcb=0#1TC=windows-7
 
Michael

gwen,
I forgot you are testing just monitoring latency and not recording latency.
HDDs are probably not the issue. I went off on a tangent when I saw your screenshot.
Grabbing at straws here.
Still , it would be good if you could describe your PC.
 
Michael

Its kind of recording AND monitoring.  What I'm simulating is a musician playing back with a backing track, which is ending up noticably out of sync.  I could theoretically just manually adjust every single cut ever done, but gosh it will look unprofessional when I have to do it just to listen back to a track we just recorded.  If it wasnt variable, sonar has a setting for that.  I still don't really understand though, I would think sonar should normally adjust this sort of value by default for people due to an inevitable small bit of lag summed between playback and overdubbing.
 
 
My computer worked flawlessly two-three years ago, and with of all things an Alesis Multimix USB 2.0.  Here should be anything you're possibly curious about :)   There are many USB devices, but I have replicated the issue with only the Tascam, mouse and keyboard.  I'm still suspecting my USB for the moment.  It doesnt explain why my other computer is showing the latency in the CEntrance utility that it is, but I dont know if thats to be expected.  I should be installing sonar on another computer to attempt today or tomorrow morning.
 

 
    
Computer Profile Summary

Operating System                 System Model
Windows 7 Ultimate (x64) (build 7600)
Install Language: English (United States)
System Locale: English (United States)
Installed: 1/31/2014 8:00:07 PM
Boot Mode: BIOS (Secure Boot not supported)                 No details available
Processor a                 Main Circuit Board b
2.90 gigahertz AMD Athlon II X3 435
384 kilobyte primary memory cache
1536 kilobyte secondary memory cache
64-bit ready
Multi-core (3 total)
Not hyper-threaded                 Board: ASUSTeK Computer INC. M4A785-M Rev X.0x
Serial Number: 102641600002722
Bus Clock: 200 megahertz
BIOS: American Megatrends Inc. 0503 09/28/2009
Drives              Memory Modules c,d
1819.58 Gigabytes Usable Hard Drive Capacity
670.58 Gigabytes Hard Drive Free Space

HP Virtual CD 4507 USB Device [Optical drive]
PIONEER DVD-RW DVR-110D ATA Device [Optical drive]

HP External HDD USB Device [Hard drive] (499.40 GB) -- drive 3, s/n WXG1A30X0460
WDC WD3200AAJS-00L7A0 [Hard drive] (320.07 GB) -- drive 0, s/n WD-WCAV2C548579, rev 01.03E01, SMART Status: Healthy
WDC WD5001AALS-00L3B2 [Hard drive] (500.11 GB) -- drive 1, s/n WD-WCASY9557327, rev 01.03B01, SMART Status: Healthy
WDC WD5001AALS-00L3B2 [Hard drive] (500.11 GB) -- drive 2, s/n WD-WCASY9646636, rev 01.03B01, SMART Status: Healthy                 8192 Megabytes Usable Installed Memory

Slot 'DIMM0' has 2048 MB
Slot 'DIMM1' has 2048 MB
Slot 'DIMM2' has 2048 MB
Slot 'DIMM3' has 2048 MB
         Local Drive Volumes
         
                
c: (NTFS on drive 0) *     319.97 GB     147.03 GB free         
d: (NTFS on drive 1)     500.11 GB     430.58 GB free         
e: (NTFS on drive 2)     500.11 GB     75.08 GB free         
i: (NTFS on drive 3)     499.40 GB     17.89 GB free         

Microsoft Shared Fax Driver     on SHRFAX:
Microsoft XPS Document Writer     on XPSPort:
Controllers                 Display
ATA Channel 0 [Controller] (2x)
ATA Channel 1 [Controller] (2x)
Standard Dual Channel PCI IDE Controller (2x)                 NVIDIA GeForce 8800 GT [Display adapter]
DELL ST2410 [Monitor] (24.0"vis, s/n XX-0X175R-XXXXX-01S-2KRU, January 2010)
VIZ E320i-A0 [Monitor] (31.5"vis, s/n LAIANLDN01000, February 2012)
Bus Adapters                 Multimedia
Standard Enhanced PCI to USB Host Controller (2x)
Standard OpenHCD USB Host Controller (5x)                 High Definition Audio Device
NVIDIA Virtual Audio Device (Wave Extensible) (WDM)
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Communications                 Other Devices
        
             HID-compliant consumer control device (2x)
HID-compliant device (5x)
USB Input Device (4x)
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HID-compliant mouse
USB Composite Device (2x)
USB Mass Storage Device
USB Root Hub (7x)
USB Virtualization Connector Driver
Generic volume shadow copy
USB Storage Use in past 30 Days (mouse over last used for details)              Hosted Virtual Machines (mouse over name for details)
      Last Used
HP External HDD -- drive 3, s/n WXG1A30X0460, rev 2002     3/4/2014 12:34:35 PM
             None discovered
 
 

Here are my current settings. 
 
imgur.com/MzxeT1M
 
imgur.com/LehhXhi
 
imgur.com/zVOTdtY
 
interestingly, cakewalk's minimum latency is the same (256 samples, 5.8sec) as the 'high' setting in the control panel.
(CEntrance prompts open the control panel, the latency dropdown is selected, then it shows up in CEntrance different latency's for each.  Medium works (4.35ms at 192 samples I think it was?) but low and lowest do not work.  They seem to work fine in fruity loops and all of my other programs though.  I'd be way curious what Tony gets as far as CEntrance and Sonar's detected latency minimums :)

Okay that's very interesting. It appears you have SONAR set to use WDM driver mode. Otherwise you'd have an ASIO Panel button where you have a Wave Profiler button on the Driver Settings page.
 
So the first thing to do is to go the Playback and Recording page in Preferences > Audio, and change the driver mode to ASIO. Then see what SONAR reports for RTL vs. CEntrance (which only tests the ASIO driver, not WDM), and set the Manual Offset on the Sync and Caching page as the difference between what CEntrance measures and what SONAR reports as suggested previously. Then try your re-record test again.
 
 

its working!!!!

driver settings:       imgur.com/dZxYeZ0
sync and caching:   imgur.com/ACh6u8P
repeatedly bounced back click track:  imgur.com/Pz2OA9N   ---- increasing in amplitude to the point of clipping and distortion, as it should be!
drum pad, played to metronome, bounced back with metronome and in perfect time:  imgur.com/HQpk0qe
 
thank you so much!!!  i have no.  freaking.  idea.  how I missed that.  I was trying everything I could before to get it so I could run youtube videos or external MP3 players while playing without messing up my sound, because sonar wouldnt share with anyyyything on WDM.  None of the other settings were working that day!    I guess it was some sort of fluke.  I guess the lesson I've learned is that even computer settings can be finicky and deserve twice-overs.
 
On the upside, I've learned lots of nice tricks.  Thank you for all the people that were so vigilant in helping me figure things out :)
 
I thought it was very odd that cakewalk wouldn't include some sort of roundtrip test and automatically account for this, but there it is.  automatically adjusting for the 661 sample latency :)
 
i'm so happy right now.  AHHHHHHH
 
^_^ thanks guys
 -gwen!
 
ps;  i am ay freaking oh kay now.  but if you're just more of a tinkering and figure-things-out-er than just wanting to help really bad type... CEntrance is getting about 46 more samples than sonar ;)