You also need to consider power management. Intel claims a 130-watt Thermal Design Power (TDP) rating for the Core 2 Extreme QX6700. That's almost twice as much as the Core 2 Extreme X6800's 75-watt TDP. That number is an outer-limit rating, meaning that fan and heat makers should design their parts to dissipate the attendant heat of a 130-watt TDP part but that in most cases, it's not going to get that hot. We suspect that Intel might be accommodating for overclocking here, as well. The new built-in digital thermometer also seems particularly overclocking friendly. The sample motherboard and fan we received didn't support the new thermometer, but Intel informed us that production boards will ship with that feature fully enabled. It's also worth noting that mainstream vendor Gateway is selling its new Core 2 Extreme QX6700-equipped FX530XL desktop factory-overclocked, and the overclocked parts are under warrantee. That a volume producer such as Gateway is going to back overclocking this chip, we have to believe that the chip's tolerance has plenty of room to grow.
If you're wondering what the future of quad-core processing looks like, AMD's 4x4 solution, which pairs two dual-core CPUs, sits on the horizon. We've talked to a number of system vendors, however, who back up our own trepidations about the price-performance and thermal issues of a two-chip solution. We'll give AMD the benefit of the doubt until we have 4x4 in our hands and have had an opportunity to test it out. We also expect that both Intel's and AMD's quad-core designs will trickle down to mainstream-priced chips before too long. Don't expect it to end there, though: Intel has already announced an eight-core server chip on its road map for the future.
OS X 10.4.8; 2x 3.0GHz Xeon 5160; 1,024MB DDR2 FB-SDRAM 667MHz; 512MB ATI Radeon X1900; 500GB Seagate 7,200rpm SATA/150
Intel Core 2 Extreme QX6700 test bed
Windows XP Professional SP2; 2.6GHz Intel Core 2 Extreme QX6700; 1,024MB DDR2 SDRAM 667MHz; 256MB ATI Radeon X1900; 74GB Western Digital 10,000rpm SATA/150
Intel Core 2 Duo X6800 test bed
Windows XP Professional SP2; 2.93GHz Intel Core 2 Duo X6800; 1,024MB DDR2 SDRAM 667MHz; 512MB ATI Radeon X1950 (underclocked to X1900 speeds); 74GB Western Digital 10,000rpm SATA/150
AMD Athlon 64 FX-62 test bed
Windows XP Professional SP2; 2.8GHz AMD Athlon 64 FX-62; 1,024MB DDR2 SDRAM 800MHz; 512MB ATI Radeon X1950 (underclocked to X1900 speeds); 74GB Western Digital 10,000rpm SATA/150