Hd5670

i have a hd5670 512mb video card, whats the best, safe overclock settings and fan speed?
OS Name Microsoft Windows 7 Home Premium
Version 6.1.7600 Build 7600
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name MARK-PC
System Manufacturer LENOVO
System Model IdeaCentre K300
System Type x64-based PC
Processor Pentium(R) Dual-Core CPU E5700 @ 3.00GHz, 3003 Mhz, 2 Core(s), 2 Logical Processor(s)
BIOS Version/Date LENOVO 58KT36AUS, 10/14/2009
SMBIOS Version 2.5
Windows Directory C:\windows
System Directory C:\windows\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "6.1.7600.16385"
User Name Mark-PC\Mark
Time Zone Eastern Daylight Time
Installed Physical Memory (RAM) 8.00 GB
Total Physical Memory 8.00 GB
Available Physical Memory 6.75 GB
Total Virtual Memory 8.00 GB
Available Virtual Memory 6.64 GB
Page File Space 0 bytes

Power supply cooler master 460w