It's happened before, silly as it is, AMD once decided that a new 8GB card needed a 4GB variant at the last minute before launch so they shipped the first batch of "4GB" cards with 8GB installed and half of it just disabled in the VBIOS. You could easily flash it to unlock the full 8GB - the one time you really could download more RAM.
Those were the Phenom Tripple Core Chips you are thinking of. What the Pencil mod did was enable the 4th core on the Tripple Core Chips. However, the 4th Core was likely a factory rejected core for some reason or another, so enabling it could lead to instability
> However, the 4th Core was likely a factory rejected core for some reason or another, so enabling it could lead to instability
It may have been a defective core, but when they make these cut-down SKUs they need to meet a quota of units regardless of whether that many salvagable defective chips roll off the line, so it's not uncommon for them to disable perfectly functional hardware. Especially as the process matures and yields improve.
I remember doing exactly that with one of my Athlon's. Don't remember if it was an Athlon XP or Athlon 64, but they'd removed a jumper on the top and you just needed a 2B pencil to join the pads to get a free upgrade.
I did that with a Phenom II X2 555. The 3rd core was stable up to around 3.8ghz if I remember correctly, whereas the 2 enabled by default were fine up to at least 4.2.
