Hardware Reference
In-Depth Information
150-watt incandescent light bulb, let it warm up, and then put your hands around it
(but do not touch it). This amount of heat must be dissipated continuously by a
high-end Core i7 processor. Consequently, when a Core i7 has outlived its use-
fulness as a CPU, it can always be used as a camp stove.
According to the laws of physics, anything that puts out a lot of heat must suck
in a lot of energy. In a portable computer with a limited battery charge, using a lot
of energy is not desirable because it drains the battery quickly. To address this
issue, Intel has provided a way to put the CPU to sleep when it is idle and to put it
into a deep sleep when it is likely to be that way for a while. Five states are pro-
vided, ranging from fully active to deep sleep. In the intermediate states, some
functionality (such as cache snooping and interrupt handling) is enabled, but other
functions are disabled. When in deep sleep state, the register values are preserved,
but the caches are flushed and turned off. When in deep sleep, a hardware signal is
required to wake it up. It is not known whether a Core i7 can dream when it is in
deep sleep.
The Core i7's Logical Pinout
The 1155 pins on the Core i7 are used for 447 signals, 286 power connections
(at several different voltages), 360 grounds, and 62 spares for future use. Some of
the logical signals use two or more pins (such as the memory-address requested),
so there are only 131 different signals. A somewhat simplified logical pinout is
given in Fig. 3-45. On the left side of the figure are five major groups of bus sig-
nals; on the right side are various miscellaneous signals.
124
18
DDR Memory
Channel #1
Diagnostics
124
4
DDR Memory
Channel #2
Thermal
Monitoring
80
10
PCIe Channel
Power
Management
Core i7
CPU
16
7
Direct Media
Interface
Power Sensing
24
Configuration
21
12
Flexible
Display Interface
Miscellaneous
286 360
CK Ground
Figure 3-45.
Logical pinout of the Core i7.
Power
