GPU: Sapphire 7950, 4L ref, (red and black case).
MB: ASRock extreme6
RAM: 8GB
CPU: intel i2500K CPU.

MINER: vertminer 0.5.3 renamed to 'cgminer.exe' living in a folder within the cgwatcher folder.
BIOS: stock, (I intend to flash it with an optimized Stilt BIOS and then gently OC for max, but conservative OC performance.)
TEMPS: 20C ambient room temps, GPU fan at about 75%, GPU temps 65C. It's in a wide open box but no box fan blowing on it.

I'm hashing at vert.bitcrush.info and getting less than 1% stale and rejected. I'm in the U.S. and pointed at their U.S. server URL. I've been testing for 48 hours.

It hashes at 273 kh/s - 280 kh/s. When restarting or starting the miner, hash readings in vert/cg/miner report wild fluctuations up to 825 kh/s for a few moments and then swing down to 180 kh/s, eventually settling in at the a fore stated rates. This card and setup is of course completely stock.

OBSERVATIONS of INTEREST:

Running any applications that access the higher functions of the GPU, like watching a movie in VLC, or firing up a CAD program, will bring the hashrate down to 20 kh/s and stick it there. No matter if vert/cg/miner is then restarted with a .bat file at that point, or the miner is restarted from cgwatcher, no effect, the card is still stuck at low hashes. Rebooting then seems to reset the card and free up its resources and it goes back to premium hashing.

Of interest, in MSI afterburner, I see that the memory use on the card is only 2054 MB of the available 3072 MB. My question is, why is it only using 1/3 of the memory on the card and might there be room for improvement, to get the card to use more of its onboard memory, or, is this a limitation of the algo, the "Scrypt N (Jane N)", algo?

The only setting that might not seem to be stock or "nominal" is that powertune is set at 20, because it is a "boost" edition card. There is a slight difference when powertune is set to 0, or 10, the hashrate is reduced to about 243 kh/s.