[Solved] Sync question

That's for syncing to an external sequencer or drum machine, nothing really to do with what's in the box. 

Thanks for the info.  So how do Sonar sync with virtual Drums, through vst protocol? and how does it sync with the sound card, in my case, would that be the USB driver?

A VST instrument like BFD is driven by the midi track. It should play each note as the event happens. 
I believe Lynx audio interfaces are solid good performers. They also have low round trip latency. 
But as Dave said, often what we call midi latency can be caused by certain plug ins that use look ahead buffers etc. 
So if what you saying is you hit your keyboard but the note takes a second or more to play, then by pass your effects bins and see if that solves it. 
 
And the Lynx if it has midi ports will show in Sonar as an available midi device. 
If your not using the midi ports then they have nothing to do with your issue. 
 

One caveat: if you're using the 32-bit BFD Eco. Bitbridge has a bug that will add an empty buffer of audio to the front end of rendered output, making it play back audibly late when the audio buffer is high.
 
Having the MIDI Prepare Using buffer too low doesn't generally cause timing errors; the more common symptom is dropped notes. I suppose that might sound like a timing error in some cases, but otherwise, I'd be surprised if changing the MIDI buffer really solved a sync problem.
 
External Insert latency depends on your round-trip audio latency, and the latency of whatever hardware you're running the signal through, which can add up if the hardware uses DSP with analog I/O and has to do its own A/D/A conversion on top of SONAR's. And SONAR's automatic Plugin Delay Compensation is going to delay everything else to maintain sync with the EI return, causing the whole project to have more latency. External Insert processing is usually something you wouldn't use until all tracking has been done, and you've moved on to the mixing stage where playback latency doesn't much matter.