Issue overclocking new amd fx 4300

Hi i just bought the new amd fx 4300 chip from a buddy for a cheap price =P the problem im having is i cant get it stable over 4.5ghz is that normal? and even at 4.5 its iffy...if i go anything past 4.5 when i run prime95 windows just automatically locks up and stays like that until i manually reboot it. i thought they could overclock far beyond that my specs are as follow

Antec 620watt power supply
Asrock 990fx extreme 3 motherboard
Amd fx 4300 processor
4gb 1333mhz ram
Asus Eah6850 video card
64gb ssd
1tb hdd
antec kuler 620 liquid cooling


If there is anything else you need to know let me know

Ps. Temps seem to be okay..32ish c at full load at stock settings and at 4.5 there at about 54c