I have 2 rigs, one with 3x XFX R9 290's, and one with 1 Asus R9 290.
Note: All 3 cards are elevated from the mobo by riser cables pcieX1 to pcieX16.
The rig with 3 cards is the one that is giving me these frozen miner windows. One day everything is fine, mining the whole day into the next. Then another day it freezes up to a couple of times. I just can't seem to figure out what could be causing this. Perhaps a new cgminer process is starting too soon after killing the previous cgminer.exe  I'm just guessing here.
The single card rig hasn't had any problems at all mining under cgwatcher supervision.

Just now another failed cgminer restart, this is from cgwatcher.log:

[8-2-2014 15:24:33]          Accepted shares have not changed for 5,033333 minutes, longer than the threshold of 5 minutes. Attempting to restart...
[8-2-2014 15:24:33]      [d] Miner.Restart begin.
[8-2-2014 15:24:33]          Restart CGMiner was requested, preparing to stop then start the miner to make sure its configuration settings are reloaded...
[8-2-2014 15:24:33]      [d] Miner.PerformStopStartRestart called. (Profile=Digger;Miner=C:\cgminer-3.7.2-windows\cgminer.exe;HasFullAPIAccess=True;Initiator=Monitor;Reason=#NAME# was successfully restarted.)
[8-2-2014 15:24:33]      [d] Miner.StopMining called: Miner=C:\cgminer-3.7.2-windows\cgminer.exe;ProcessID=4728 (True);BatchProcessID=0 (False);Config=C:\cgminer-3.7.2-windows\cgminer.conf;Arguments=--config C:\cgminer-3.7.2-windows\cgminer.conf;HasFullAPIAccess=True;KillOnReadOnlyAccess=True;IsBatCmdFile=False;ProcessID=4728;.
[8-2-2014 15:24:34]          CGMiner process closed outside of CGWatcher!
[8-2-2014 15:24:34]      [d] Miner.StartMining (for restart) called. [Profile=Digger;MinerFile=C:\cgminer-3.7.2-windows\cgminer.exe;MinerFileUsed=C:\cgminer-3.7.2-windows\cgminer.exe;MinerExecutable=C:\cgminer-3.7.2-windows\cgminer.exe;Config=C:\CGWatcher-1.3.5\temp.conf (C:\cgminer-3.7.2-windows\cgminer.conf);Arguments=--config C:\CGWatcher-1.3.5\temp.conf;Anticipated Port=4028;Used Port=4028;HasFullAPIAccess=False;IsBatCmd=False;BatCmdPath=C:\cgminer-3.7.2-windows\cgminer.exe (C:\cgminer-3.7.2-windows\cgminer.exe);LastKnownInstanceCount=0/0]
[8-2-2014 15:24:35]      [d] Miner.IsProcessAlive(4792) returns True. [First try, process is alive.] (CPID4792/CMPID=4792/CBPID=0)
[8-2-2014 15:24:35]      [d] Waiting for CGMiner to initialize API. Process 4792 alive=True, minerid=4792.
[8-2-2014 15:24:36]      [d] Watch for miner, expected process is 4792 (alive).
[8-2-2014 15:24:36]      [d] CGMiner process is running using ProcessID 4792, expecting port 4028.
[8-2-2014 15:26:15]          CGMiner process closed outside of CGWatcher!
[8-2-2014 15:26:15]      [d] Finish wait for miner to start, process is 0 (not alive).
[8-2-2014 15:26:15]      [d] CGMiner process 0 not alive at Miner.StartMining exit.
[8-2-2014 15:26:15]          Start miner failed on 1st attempt. Killing any remaining processes and trying again.
[8-2-2014 15:26:15]      [d] Miner.IsProcessAlive(4792) returns False. [First try, test process is nothing.  ex: Process with an Id of 4792 is not running.] (CPID0/CMPID=0/CBPID=0)
[8-2-2014 15:26:15]      [d] Miner.StartMining (for restart) called. [Profile=Digger;MinerFile=C:\cgminer-3.7.2-windows\cgminer.exe;MinerFileUsed=C:\cgminer-3.7.2-windows\cgminer.exe;MinerExecutable=C:\cgminer-3.7.2-windows\cgminer.exe;Config=C:\CGWatcher-1.3.5\temp.conf (C:\cgminer-3.7.2-windows\cgminer.conf);Arguments=--config C:\CGWatcher-1.3.5\temp.conf;Anticipated Port=4028;Used Port=4028;HasFullAPIAccess=False;IsBatCmd=False;BatCmdPath=C:\cgminer-3.7.2-windows\cgminer.exe (C:\cgminer-3.7.2-windows\cgminer.exe);LastKnownInstanceCount=0/0]
[8-2-2014 15:26:16]      [d] Miner.IsProcessAlive(4340) returns True. [First try, process is alive.] (CPID4340/CMPID=4340/CBPID=0)
[8-2-2014 15:26:16]      [d] Waiting for CGMiner to initialize API. Process 4340 alive=True, minerid=4340.
[8-2-2014 15:26:17]      [d] Watch for miner, expected process is 4340 (alive).
[8-2-2014 15:26:17]      [d] CGMiner process is running using ProcessID 4340, expecting port 4028.
[8-2-2014 15:26:22]      [d] CGMiner running and API initialized on port 4028, process matched to profile Digger.
[8-2-2014 15:26:22]      [d] Finish wait for miner to start, process is 4340 (alive).
[8-2-2014 15:26:22]          CGMiner was successfully restarted.