Turbo V crashes when I try to lower the bclk

Hi,
I have a P7H55D-M pro with an i3 540 and g. skill 2gb 1600mhz, it's running stable at 150mhz bclk and I'm using turbo key to take it to 178mhz when gaming (also stable).

Turbo key can be turned on fine, but the computer crashes when I try to turn it off, no blue screen or anything, it just reboots.

I tried upping the clock manually with turbo v and it worked but if I try to drop it even 1 mhz it reboots, does anyone know why? I mean, I can easily reboot if I want to lower the clock, but I'd like to be able to do it on the fly, if possible.

thanks

more info:
I usually run:
bclk: 150mhz (3.45 ghz)
core voltage: 1.12v
fsb ram:4:16
CL: 8-8-8-24
temps: 30c idle, a little over 50c under load (prime 95)

For gaming:
bclk: 178mhz (4.1 ghz)
core voltage: 1.28v
fsb ram:4:16
CL: 8-8-8-24
temps: 35c idle, average 66c under load, never hits 70c

speedstep is always disabled, voltages are fixed