I installed the chip and ran Tcasemax, unfortunately my heart sank when a 85W TDP was displayed. Now I'm thinking, maybe the chips that overclock so well do so because of their ability to draw more power. In order to reach a high clock speed, a sufficient amount of power is necessary. Therefore if a chip is already pulling enough current (ie. those with high TDP) then no Vcore bump is needed (hence the high clocks on stock voltage). That would also mean low TDP chips (like the wonderful 35W TDP I would love to get my hands on) should be pretty bad overclockers as even with Vcore bumps they have a hard time pulling enough power.
If that's correct, then the good overclock steppings should have high TDPs and bad overclock steppings low TDPs (assuming that within each stepping, TDPs are similar). Unfortunately most user postings on their Opterons either list the stepping or the TDP, but rarely both so it is hard to see if there is any truth in this thinking. However I'm hoping enough SPCR forum readers have had experience with these Opterons and can share TDP, stepping, and overclock/underclock experiences, and their take.
From xtremesystems Opteron thread there is a collection of stepping/overclock data where most of their CCBBE and CCB1E steppings reach 3ghz or more and many of the CCBWE steppings being poor overclockers.
My experience using an ASUS A8N-VM CSM mb and PW200M DC-DC PSU (power figures = AC Consumption with loading via Orthos)
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Opteron 170 CCBBE0615DPMW 85.0W TDP STATE Clock Vcore Idle- Load STOCK 10x200 1.35v 68W - 117W UNDERVOLT 10x200 1.15v 59W - 97W UNDERCLOCK 5x200 0.90v 50W - 66W OVERCLOCK 10x240* 1.35v - 128W OC/UV 10x240* 1.25v - 113W
For comparison, the single-core Opty 144 (44.1W TDP) it replaced ran about 7C cooler.
IDLE 5x200 0.80v 50W
LOAD 9x200 1.00v 63W