I would say, that both are not the "same" one (QX6700) is more home friendly than the other one (Xenon X5355).
QX6700
Processor features Intel Smart Memory Access, Intel Advanced Smart Cache, Intel Wide Dynamic Execution, Enhanced SpeedStep technology, Execute Disable Bit capability, Intel Virtualization Technology, Intel Advanced Digital Media Boost, Intel Extended Memory 64 Technology
X5355
Processor features Intel 64 Technology, Demand Based Switching, Intel Advanced Smart Cache, Enhanced SpeedStep technology, Intel Virtualization Technology
also notice that the bus speed are different 1333MHZ is the x5355, comparable to the QX6700 that only has 1066MHZ.