And yes... bit's post was very enlightening. Thank you, bit.
 

I tried a lower playback buffer size of  128 samples, but the lag is still there....
Guess I just have to live with it?

Does it happen ALL the time or just when you haven't pressed play for a while? Like I said, when my hard drive falls asleep it causes a lag. That's a Windows Power Management/Hard Disk Management issue. Most "optimization" guides have a section of setting things so the hard drives stay active and ready at all times.

Do you have "Always Open All Devices" checked?  I've found that that can have an impact too.

Bypass all fx just to rule it out? There is a global fx button on the control bar.

Exactly. Try disabling FX or PC's. If you have lots of them, this will surely slow you down. Freezing your tracks may help as well. You It takes the ability away to adjust FX, but for those tracks you aren't tweaking, it's quite useful.
 
Also try disabling the 64-Bit Engine as well, if it's enabled.

I couldn't see an i7 system getting that bogged from FX on a single track. I mean check it out but with a QC, an i7 and the recommended amount of RAM it shouldn't be struggling.

Its one of these things, so just go thorough them and rule them out.

• Try using a different driver mode. If your using WDM, try ASIO, If your using ASIo, try WDM
• Are your buffers in Que set to 2? It should be
• Lower your playback I/O buffer to 64 or 128 or 256
• Update to the latest driver for your sound card. Go to the sound crads website and check
• Some Non Native effects can cause a slight delay
• Your ASIO or WDM settings should be set as low as possible without causing any artifacts. Each project is different, so you may need different driver settings for each project, depending on whats in each project and track counts and so on.
• Sometimes, something in you PC, like a program running in the background may effect performance

CJ

As I said in post four, try disabling all effects by pressing "E" on your computer keyboard.  Did you try this?
 
It doesn't matter how powerful your computer is, if it has any latency inducing effects on a track or bus, it will induce latency, unless it is capable of time travel.

I would certainly try jb101 and freezing the tracks as a test.
 
Could Bit-Bridging have any effect? I know it certainly has a negative impact during playback, but do the buffers fill with pre-determined bit-bridging FXs, and that Bit-Bridging induces even more latency?