1.55v for my 1100T to be stable at 4ghz with prime95 safe?

if the temperature is below 60C full load do not worry, though vCore 1:55. I know the X6 will be stable 4GHz with the Vcore 1:52 or more depending on hardware components and coolers.
x6 indeed need more vCore to be stable at 4GHz. was normal and secure. Use of 4GHz or more are only used for the Benchmark or competition only.

but for daily use 3.8GHZ just try it also depends if you want.
3.8GHZ stable with 1:44 ~ 1:45 vCore voltage CPU that is recommended by AMD and is very safe for long-term

Try enabling "Load Line Calibration" and set it to 12.9%. That should prevent your vcore from dropping so far under load and allow you to lower vcore overall.

THANK YOU   I DID WHAT YOU SAID AND GOT IT STABLE AT 1.47V  

Hey there i got almost the same setup as you. For some reason i can't get mine to oc to 4ghx stable plus heat is a big issue for me. I was wondering if u could post some pictures of ur bios. I'm running the same mobo and cpu but i got ddr3 1300.
My clocks are: 666.7mhz 3:10 9-9-9-24-33
That's with
fsb=200
mul=20
vcore @ 4.875
with everything else on auto
I tried the same nb and ht as your first post but mine wouldn't boot
Also what kinda cpu cooler do you have
Any help would be appricated =D

4.875 may be too high of a voltage for 4.0 im stable 4.2 @1.46 and if your overclocking n/b and h/t you should lock in the voltages for them
get your heat under control before you get to far into overclocking
Just a reference my system runs
n/b 3104 @ 1.2875
h/t 2882 @ 1.400
These settings most likely won’t get you stable but it may be a good reference.
check you hardware specs and make sure your able to achieve these numbers before you try them and watch your temps
i could not get anywhere close to this overclock without liquid cooling as my n/b would over heat right away
Temperatures are a major factor when overclocking as hardware destabilizes under high heat