Sam2008: thank you!

Works perfect. However quick qs: does coremask value override the mask_high/mask_low parameter?

What I mean is if I set:

index=0xc0010070
high=0x00000000
low=0x5000340A
mask_low=0xFFFFFFFF
mask_high=0xFFFFFFFF
coremask=0b0111

Will it write 0x5000340A to core4 or skip it reading the mask_low=0xF?

Could you not use mask_low/mask_high values 0/1/2/3/4/5/6/7/8/9/A/B/C/D/E/F to do the same?
i.e. using the above, me wanting to write to core 3 (340A) only=>

index=0xc0010070
high=0x00000000
low=0x5000340A
mask_low=0xFFFFF777 (mask 0111b)
mask_high=0xFFFFFFFF

Would this work?

TBH only now has Phenom really become insanely tweakable and fun to play with.