Should I be concerned?

[ATIorNvidia]

So I decided to start clocking my 5870 (using Sapphire TriXX), so I fired up Furmark and first ran it for about 15 minutes at stock speeds. Everything was fine, so I set the Core straight to 900, and from there, went in 5mhz increments until artifacts started to show up. When I hit about 955 core, I started artifacting, so I backed down to 925mhz, but was still artifacting, then I backed down to 900, then stock, then even below stock (~800mhz) but the artifacts still wouldn't go away.

Anyway, I fired up a game, and that was artifacting too.... so I ended up restarting Windows, and they disappeared. I'm back at stock now and everything seems to be fine.

P.S Voltage/mem clocks weren't touched yet.

 

[ATIorNvidia]

I think there may be a problem with the card. I notice some extremely subtle artifacts when I'm playing BF3. Like, I'll see a small black square appear on the floor and disappear within a split second, and this is at stock speeds. It doesn't happen in anything else, nor has it happened in the Heaven benchmark or Kombuster/Furmark?

Using 11.10 drivers.

 

[ATIorNvidia]

I have another rather annoying problem. I've managed to get 950/1200 stable in games/benchmarks, but sometimes when I switch user, log off, or put my PC to sleep/try to log on again), the PC will hang or the screen will go all fuzzy, which forces me to restart. When in Windows, it's perfectly fine.