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crash. That’s because while you can cut power to large sections of the execution core, the cache can tolerate
only so much decrease in power before blowing up. With Core i7, Intel separates the power circuit, so the
cache can be run independently. This lets Intel cut power consumption and thermal output even further
than before. Furthermore, while the Core 2 CPUs required that all the cores were idle to reduce voltage,
with Core i7, individual cores can be turned off if they’re not in use.
Turbo mode exploits the power savings by letting an individual core run at increased frequencies if
needed. This again follows Intel’s mantra of improving performance on today’s applications. Since a major-
ity of today’s applications are not threaded to take full advantage of a quad core with Hyper-Threading,
Turbo mode’s “overclocking” will make these applications run faster. For more information on how you’ll
set up Turbo mode, read our sidebar below.NEW SOCKET ON THE BLOCK
So all this CPU goodness and performance will drop right into that $450 LGA775 board you just bought,
right? Of course not. Ung’s Law dictates that the minute you buy expensive hardware, something better
will arrive that makes what you just bought obsolete.
Intel isn’t doing this just to piss people off (although a history of such behavior has had that result).
Since Core i7 moves the memory controller directly into the CPU, Intel added a load of pins that go directly
to the memory modules. The new standard bearer for performance boxes is the LGA1366 socket. It looks
functionally similar to the LGA775, with the obvious addition of more pins. More pins also means a bigger
socket, which means your fancy heatsink is also likely headed to the recycle bin. LGA1366 boards space
the heatsink mounts just a tad bit wider, just enough to make your current heatsink incompatible. There’s
a chance that some third-party heatsink makers will off er updated mounts to make your current heatsink
work, but that’s not known yet.
What will be interesting to heatsink afi cionados is Intel’s encouragement that vendors rate the heat-
sinks using a unifi ed thermal rating that will be tied to the Turbo mode settings. For more information, see
the Turbo mode sidebar below.THE SECOND COMING
Intel is adopting more than just AMD’s integrated memory controller with its new Core i7 chips; it’s also
adopting AMD’s abandoned Socket 940/754 two-socket philosophy. For the high end, the LGA
socket will off er tri-channel RAM and a high-performance QPI interface. For mainstream users, Intel will
off er a dual-channel DDR3 design built around a new LGA1066 socket late next year. LGA1066 isn’t justTurbo mode might sound like a feature left over from the TV series Knight Rider, but
it’s more neat than cheesy. You already know that Core i7 CPUs closely monitor the
power and thermals of the chip and use any leftover headroom to overclock the indi-
vidual cores as needed. But just how does it work?
From what we’ve surmised by examining an early BIOS, you will be able to set
each type of core scenario based on how far you want to overclock, given the load. For
example, with applications that push one thread, you could set the BIOS to overclock,
or rather, turbo that single core by perhaps three multipliers over stock. You would do
the same for two-, three-, and four-core scenarios.
The BIOS will also take into account the thermal rating, or TDP, of the cooling
system you’re using. If you’re using, say, a heatsink rated for 150 TDP, the BIOS will
overclock to higher levels than it would with a 130 TDP unit. You would manually set
the heatsink’s rating in the BIOS, as there’s no way for the heatsink to communicate
with the motherboard directly.HOW IT WORKSIntel’s Turbo Mode Technology
Knight Rider, but
it’s more neat than cheesy. You already know that Core i7 CPUs closely monitor the
power and thermals of the chip and use any leftover headroom to overclock the indi-From what we’ve surmised by examining an early BIOS, you will be able to set
each type of core scenario based on how far you want to overclock, given the load. For
example, with applications that push one thread, you could set the BIOS to overclock,
or rather, turbo that single core by perhaps three multipliers over stock. You would doThe BIOS will also take into account the thermal rating, or TDP, of the cooling
system you’re using. If you’re using, say, a heatsink rated for 150 TDP, the BIOS will
overclock to higher levels than it would with a 130 TDP unit. You would manually set
the heatsink’s rating in the BIOS, as there’s no way for the heatsink to communicateTechnology Watch List
The good news is that you’ll get fi ne-grain control
over the Turbo mode in the upcoming Core i7 CPUs.