These are Engineering Sample stepping and would not usually be purchase.
Q4GG is stepping 4
Q9WW is stepping 6 same stepping as the retail version.
On the net the Stepping 4 T9500 is much cheaper than the stepping 6. Q9WW. What is the difference.?
Having tested both stepping this is what I found.
The stepping 4 have a fault temperature sensor, and most software like CPUID could not detect.
But this alone would not justified the price difference of the processor. It is actually the CPU working voltage
Mhz/step Q4GG Q9WW
800Mhz 1V 0.925V
1.2Ghz 1.05V 1V
1.6Ghz 1.075V 1.05V
2.0Ghz 1.15V 1.1V
As you can see from the table at the same frequency the stepping 4 CPU is consuming more power that the stepping 6. It is consuming more power then a menron CPU. and hense you could expect the laptop to be running hotter as well.
Instruction wise there is hardly and difference between the 2 CPU so all your application would still run fine, just a bit hotter.