It looks like that 'Play' VST allow you to load multiple instruments.  I am curious as to what you have loaded into 4 instances of it.
 
Here is a FAQ page for it:
 
http://www.soundsonline.com/knowledgebase
 
Also, Play seems to have an internal convoluted reverb in it, and IF you are using this, it may well cause all kinds of latency issues, due to the way convoluted reverbs do their processing.  Please post back and clarify if any of the Play instances are using this particular type of reverb, in addition to explaining what you have loaded into the 4 Play instances.
 
Also, Play seems to have a couple of 'flavors' of samples for given sounds, where 1 version loads a massive number of samples for an instrument, and they also have a 'light' version, which has many fewer samples.  Something to consider, if you are pushing your boundaries too far.
 
Bob Bone
 

Please note the DPC Latency Checker is not compatible with Windows 8 and will give false readings.

Good point, sharke.  The OP had indicated using Win 7 earlier, but it is still good to know about it not working on Win 8 for his next computer.  :)
 
Bob Bone
 

They actually recommend running multiple instances so your computer can take advantage of it's multiple cores.  I also did try turning off the reverb in Play.  
 
I am doing the larger versions of the patches, but I have them all loaded into memory.  Even with that though, I'm only at like 10% or so of system memory used.
 
It will be interesting to see what the DPC Latency checker says.  Maybe there's something going on in the background I don't know about.  Also, I know I didn't install drivers for the onboard sound cards, but I wonder about disabling them in the bios?

Some folk seem to choose to disable their on-board sound.  I use mine, as do a lot of folks.  It should have nothing to do with your issues.
 
So, how about working at it from the standpoint of starting with a single instance, and making sure that works OK, then building up to see when issues start?
 
Just a thought.
 
Bob Bone
 

Ok, so I ran the DPC latency checker, average latency seems to be around 50-100 us.  It will spike to 200-300 us when opening a new program like firefox or chrome (max 373).
 
I then tried running Sonar with it, no appreciable spikes, but the sound is still stuttering.  I then started deleting plugins, but the crakling was still there when I got all the way down to 1 instance of Play.  
 
Note that this project was playing fine with 4 instances of Play, and then it stopped.  
 
I then tried lowering latency in the Scarlet mix to 4ms and 3 ms, nothing.  at 2ms, I got the audio has stopped warning.
 
Very strange...
 
I load up a new project with several instances of play, but Session Drummer, Punch, BreakTweaker, Stylus RMX, Stuttter Edit, and that seems to be playing fine (for now) Latency at 5 or 8 ms.
 
Note that I still have DPS running in the background, and even with all this playing, I'm right around 50 us.  Also note that even with the other project's audio messing up, there were no latency spikes.
 
I think next, I'm going to try and recreate that project from scratch, something funny has to be going on.
 
 

Just a note, If I run my Scarllet under 7 ms I will have issues, Focusrite recommends 9-12 for general recording and editing, You would only run it down to the lower buffer setting if attempting to use Guitar Rig or real time effect monitoring.
I wrote this in the other thread in Hardware forum so you may have missed it. Focusrite uses a different language for the buffer setting and people get it mixed up. 9ms is about 256 Buffer. 3 ms is like a 32ms buffer which very few systems can perform at. So Bob is actually sending you in the wrong direction.. Just leave it at 9 or 10, the default,  until you sort this out. 
 
You reported RTL is higher than mine. On the 3 totally different computers I have used with the Scarlett, my RTL is around 27-32ms. That's with the Buffer setting at 9ms. 
 
I also had mentioned the DPCLAT test way back before you did the re install of your OS. Glad that was reporting OK as that's real important information when experiencing dropouts. 

I bounced down all the tracks, and the crakling went away, but as soon as I unbounced one, it came back.
 
I then tried a new project, no crakling this time but sound would just drop out, at 5ms, I raised it to 8ms and that seemed fine.   No Crakling and it seems no dropouts.  Also turned on reverb, that seemed fine.
 
Does anyone have Hollywood strings?  I can send the the test project, see if they get dropouts.  Maybe that project got corrupted some how?  And the dropouts on the other projects are just from too low latency?
 
 

My suggestion to try bringing it way down was to see the effect it had on the situation - thanks to the other poster for jumping in, as I do not have the same hardware as the OP and really do not much to offer, since DPC latency Checker seems happy with the system.
 
Bob Bone
 

Well, I will montor the situation then, and see if it recurs in the new project with the same tracks I created.  Also, I might try them in Reaper or something.
 
Thanks again for the help guys :)