it does seem strange that it is happening in your environment. another suggestion is try running sysinternals process explorer to see if there is something else causing this in the background

UPDATE: Okay, now with my FF800 drivers properly reporting 3.118, ASIO appears to just not be an option even with Compatibility in Win8.  Memory and static creep issues are back :(

I'm testing WASAPI now:
-Stream > 16 bit data as 32 bit PCM, left justified
DMA Buffer sizes for each respective sample rate:
11 samples for 11025 hz, 22 for 22050 hz, 44 for 44100 hz, 48 for 48000 hz, and 96 for 96000 hz..  Those numbers follow for each of the 16 and 24 bit mono and stereo methods.

So in WASAPI I've currently set my buffer size to 5 msec (240 samples) with a reported effective latency at 48khz/stereo = 5.0 msec.

While Sonar itself gets a little sluggish the CPU utilization goes from idling at 1-2% with the audio engine still live to "full load" at 14%.  Memory isn't piling up and crystal clear audio.  I may have to settle with working outside of ASIO for now.  Here's hoping I don't come back Monday to find the issue returned. This will be the last time I can tweak and test until then.

For ME, ASIO wasn't an available option until I de-selected the audio device.  THEN, I could choose ASIO, which would find and auto-populate for my audio interface for ASIO mode.
 
Bob Bone
 

Switching Driver models and letting Sonar rescan the system for available ASIO drivers works as it should.  I can select the FireFace ASIO option and all of my hardware inputs and outputs populate.  IT was running stable, but for whatever reason - even at the maximum buffer size, the memory leak and static creep issues persisted no matter what I removed or tried deleting from the project. 
 
It is project-specific.  I tried over a dozen other projects in various stages (including finished ones which were loaded down quite heavily).  Several of them gave issues but I cannot seem to pin my finger on what specifically is causing it.  It was hit and miss with plugins, projects that used regionFX, Bounced/comped take lanes with multiple lanes.  Simple stem mixing for masters.  Multi-aux patch points for 4-5 parallel compression techniques (Brauerizing vocals).  Numerous projects worked fine, just arming a track and enabling input echo - it never resulted in the memory leak/static creep initiating.  I can't seem to find what in particular about the projects in question now open and immediately begin memory leak and static creep on playback as long as the audio engine.

Are you referring to this? https://technet.microsoft.com/en-us/sysinternals/bb545021.aspx

Soulburned
Are you referring to this? https://technet.microsoft.com/en-us/sysinternals/bb545021.aspx

he is, yes

Try creating a bundle file (.cwb) of the problematic project and then open (unpack) it again in SONAR.
 
Although you mentioned you didn't use Audiosnap (but maybe inadvertently), creating a bundle file would get rid of any AS traces.
 

I'll give that a try on Monday when I get back into my studio.  I was also pondering if it had anything to do with audio clips and am going to try just doing a bounce of the vocal tracks that I have comp'ed and just create new audio tracks and bring those bounces back in, I can live without having access to those audio clips since we're going to re-track some things. 

May have something to do with bounced regionFX post-flattened-comps.  I always create entirely new tracks when we track new versions of something just to make managing take-lanes easier and not get bogged down with sifting through vocal passes with various different directions.

Soulburned
Me too.  It's an onboard FW 400 port.  VIA chipset is reported (Driver version 10.0.14393.0). 

Pretty shocked that a board of that caliber would use a VIA cjipset for FW,   While that would most likely would not cause an issue with an RME unit you could try a pcie FW board with a ti chipset.

I'll have to look into getting a card to test.  There was a couple on Newegg between $35-$55; some generic card with TI Chipset: XIO2213BZAY, and the SIIG model with TI chipset XIO2213 which has the best rating on Newegg's site.  Might have to call up my Sweetwater Rep tomorrow and have a quick chat.