Unlocking fourth core in the athlon II x3 450

i have a biostar A880G+ mother board but when i unlock the core and the computer reboots i get a hyper transport sync flood error what does this mean and how can i fix it ?

I would suggest a modest voltage bump. I believe this can occur when the CPU doesn't get enough power. as you are trying to unlock a core this may be necessary. you could also look for something like "load line calibration" in the BIOS which helps prevent vdroop. of course its also entirely possible your 4th core is bad, and it was disabled for a reason.

start at stock voltage, whatever its at now. and go up one bump at a time. the next highest voltage your board goes to. if you get it to boot into windows run prime 95 and watch your CPU temps. if prime 95 fails or it crashes go up another notch and repeat. if you are on stock cooling really watch your temps in prime 95. if its not stable by 1.41V I'd say you aren't going to get it. if the temps go past 55°C I would shutdown and drop the voltage.

really you're following the same procedure as overclocking, you want the lowest possible voltage it will be stable at.

if your at 28°C under load it shouldn't even get close to 55°C that was more of a Max temp I would allow during testing, on the off chance you had poor case ventalation, or sitting on the equator. I should have specified that. (AMD says Max is 75°C I've been up to 65°C during over clock stress tests)

I think CPUZ is having issue uses with the voltage reading. stock is 1.375 I believe and AMD says 1.4V Max. you are essentially turning it into an X4 though, which has a higher range.... something else that might cause that error an unstable power supply having voltage fluctuations, or the motherboard doing a poor job of regulating the voltage. that could also explain the voltage CPUZ is seeing. is it stable in prime95 without trying to unlock it?