I'm still not sure what EXACTLY is *really* different
about the Q6600 G0 vs the B3 other than LABELING.

From Intel's PCN Document:
Description of Change to the Customer:
The Intel® Core™2 Quad processor Q6600 and Intel® Xeon® processors X3220 and X3210 will undergo
the following changes for the B-3 to G-0 processor stepping conversion:
• CPUID will change from 06F7 to 06FB
• New S-specs for converting products
Ok so they changed a couple of labels on the package
and in the ID codes stored in the chip. No big deal.

• The converting products will change from the 2005 Performance FMB(105W) to the 2005
Mainstream FMB (95W)
Ok, so they found that 99.99% of their actual parts
never REALLY used 105W and that was too conservative
of a maximum specified "possible" temperature, so they
lowered the specified number on the label to guarantee
that they'll all use 95W or less under whatever test
conditions they use. For all I know 99.999% of the
B3 stepping chips ALSO use less than 95W under the same
test conditions. It's not clear that they actually CHANGED
anything to make this G0 take LESS power, they may
have just changed their guarantee / test criteria.

BUT if they DID actually reduce the true "real world"
power consumption of G0 vs. B3, HOW did they do that?
You don't get less power consumption for free; you
could slow something down so that there's
less performance SOMEWHERE so that less power on
average is consumer.

They certainly didn't do a die shrink to 45nm for G0,
since that's not specified as a change, the voltages of
G0 and B3 are the same, and so on.

So is this just a reLABELING of the guaranteed temp.,
or do the G0 chips REALLY use LESS power doing the same
things as the B3s, and if so, WHY?

• The Electrical, Mechanical and Thermal Specifications remain within the current specifications.
Intel anticipates no changes to customer platforms designed to Intel guidelines.
o Tcase for the Intel® Core™2 Quad processor Q6600 and Intel® Xeon® processors
X3220 and X3210 on G-0 stepping has been increased by 11 oC. Tcontrol offset will
remain the same relative to increase in Tcase which will help reduce acoustics
Ok so basically they are allowing the chip to run
HOTTER on G0s because they reLABELED the max Tcase
value. Translation: they got too many reports of people's
CPUs hitting the thermal limit and shutting down, and/or
they got too many complaints of PCs that were too noise
with the CPU fan running at 100% 'always' because the
Tcase under load was near the old 'limit'. So they said
"ahh let it run hotter and quieter, it won't change much
the number of CPUs that burn out under warranty, but
it'll let us sell a lot more because they don't sound like
rocket engines and trigger too many temperature warnings".

Customer Impact of Change and Recommended Action:
Minimal re-qualification and/or validation is expected for the G-0 stepping conversion due to no feature set
changes between the B-3 and G-0 steppings. Thermal qualification may be required due to increase in
Tcase.
Ok so if your poorly ventilated micro-ATX was about
to melt down before, it'll be worse now because they
let the CPU fan spin slower and the CPU get hotter.
This has nothing necessarily to do with any REAL
electrical change between G0 and B3.

The Intel® Core™2 Quad desktop processors Q6600 and Intel® Xeon® processors X3220 and
X3210 G-0 stepping will require a BIOS update.
Ok why the heck would it need a BIOS update, REALLY?
Presumably BIOSes ALL know how to read
Tcase MAX, Tcontrol FAN, CPU ID, etc. out of ANY
similar Intel Core 2 DUO/QUAD processor, and though
the numbers stored for those values changed slightly,
they say NOTHING else of a FUNCTIONAL electrical /
thermal nature changed with G0 stepping.
The voltage did not change, the frequency did not change,
it has no new 'features' or instructions.....

So it seems confusing why you'd NEED a BIOS change;
even the "GENUINE INTEL Q6600 G0" or whatever
processor model description ID string is hard-coded
into the CPUID instruction text (as far as I recall),
so even just to display the text identification of what
your CPU is, the BIOS would need to do NOTHING
new compared to the way ANY other Intel Core2
DUO/QUAD processor has always worked.

So enlighten me, EMPIRICALLY is there any
PERFORMANCE difference or
ACTUAL RUNNING TEMPERATURE difference between
B3 and G0 Q6600 when the
Vcore / Frequency / CPU fan speed / program running
is forced to be the same in a fair test?

Sounds like they changed NOTHING useful, or if they did,
they MIGHT have lessened the ACTUAL power/temperature,
and IF they DID it, I have yet to see a good explanation
of HOW and IF there were any performance sacrifices to
do that.

Sure you could find some manufacturing process change
that might get you 10% better thermal/electrical efficiency
by using a lower resistivity metal or better quality silicon
or lower loss dielectric or whatever, but since the
HighK dielectric and 45nm and other major fab. process
related changes are only happening for PENRYN et. al.
what's the deal with THIS change, really?