I finally managed to lower the memory clock on my card using ATI Tray Tool! 
Also I tweaked air flow a bit and I am down to 72°C now with 1028/425 Mhz on stock voltage with stock cooler, also getting about 270MHashes/sec. Seems running fine too for about 30 minutes now, will see if it stays this way.
Also I tweaked air flow a bit and I am down to 72°C now with 1028/425 Mhz on stock voltage with stock cooler, also getting about 270MHashes/sec. Seems running fine too for about 30 minutes now, will see if it stays this way.