I was under the understanding that none of the thoroughbred b's were superlocked but some (or maybe all) needed to be unlocked. There are quite a few links on the web about unlocking locked thoroughbreds, like the wire trick I'm referring to. In the link below, it says it's for t-bred b's.
Thoroughbred b's are always unlocked with some chipsets and in some motherboards, but not in all chipsets and all motherboards. Some of us with older/crappier motherboards need to do a wire trick to unlock them. My a7n8x can unlock them all without additional modding (I think, haven't tried, but I've read that it's true. I use a barton in that mb.)
The chip is a 2600+ thoroughbred B (266 fsb version).
AXDA2600DKV3C
JIUHB
0337MPM
I am trying to just get it to run in spec in an Asus A7A266 rev 1.03 motherboard.
When I put the chip in initially, and used jumper free mode, it would boot into safe mode, but then no matter what I set the FSB to (the multiplier was locked in bios), the pc would not boot. Each time I changed it I had to clear the CMOS. The multiplier coming up in this case was incorrect (I think it came up 10.5, but not sure, it should be 16).
I tried changing the multiplier and FSB manually with the dip switches, but when I did this, the chip would never boot.
I did the wire trick I'll link below. After doing this, I was able to use any combination of fsb and multiplier (from 5.0 to 12.5) and the machine booted and ran just fine (albeit under spec, as it should be at 16.0x).
http://www.abxzone.com/forums/showthread.php?s=&threadid=31987&highlight=wire+trick
In jumperfree mode, the multiplier was still locked, but locked at different numbers, seemingly randomly. It was locked at various times at 8.0, 10.5, 5.5, 5.0, 12.5, and a few others. I was unable to figure out where the number was coming from in jumperless mode. In jumper mode, I had control over the multi.
The multiplier is actually correctly reported in the bios, as I benchmarked it at many different multis and got appropriate results on Sandra.
I still believe the chip was locked but was unlocked by the wire trick. I've seen a lot on the web about unlocking tbred b's.