Hi, my system is :
Case : Thermaltake Soprano DX, 12cm Front Fan , 14cm Rear Fan, 9cm Side Fan Scythe
Power Supply : Thermaltake 650 W
Mobo : ASUS P5W DH Deluxe WiFi, ASUS 6cm HeatSink Fan 6cm, BIOS 2004
CPU : Intel Core Duo E6700 with Thermaltake CL-P0371 TMG I1
RAM : 2 X 1 Gb Kingston DDR2 PC6400 533 5-5-5-15
Graphics Card: ASUS 8800 GTS 320 Mb HTDP
HD : 1X 150 Gb WD Raptor SATA, 3X 500 Gb WD SATA
Sound Card : Creative Sound blaster X-fi Platinum Fatl1ty Champion Series
OS : Vista Ultimate Greek

I tried to OC but I only get 3,06 Ghz with the 15% AI OC predefined profile.
With all the other auto options (30 % etc) I had no luck.
With 30 % (3,2 Ghz) after 5mins under ORTHOS priority 9 the pc freezes.
With some other options doesn't boot or windows doesn't start and after restart (sometimes) get bios message about high

voltage.
In CoreTemp I get at Idle 40-42 and at full load 49-51 C.
Can someone please give me a safe starting point for manual oc (voltage,timing etc) and any other options on BIOS setup

('cause I see much higher speeds than mine) ?
If any other infos needed,please let me know.

TIA