Transmeta Efficeon Mobile CPU Series
In mid-October 2003, Transmeta introduced
us to their next generation of mobile processors, the Efficeon
family. Beginning with the TM8600 processor, the Efficeon line succeeds the Crusoe
processor which is now at the end of its life. The
Efficeon processor is a dedicated mobile processor, intended for compact applications
where heat and battery life are the major concerns next to performance. In some respects the
Efficeon is an evolutionary upgrade of the Crusoe processor architecture, but in other
areas it breaks completely new ground, especially for a mobile chip.
Efficeon was designed to prove that Transmeta
still has what it
takes to meet the challenge of Intel's successful Centrino chip. The Efficeon
was in the works before the then-codenamed Intel 'Banias' was launched, but
it has yet to have the same effect on the market. Recent years
have seen much of Transmeta's long-battery-life thunder stolen by Intel's
vastly improved mobile chips. While the (toasty hot) Intel Centrino has finally proven that consumers
can have an Intel processor-based notebook with
excellent battery life, had the world not first experienced the Transmeta
Crusoe this mobile processor renaissance may never have
models of Efficeon are currently available: The new TM8800, the TM8600 and the
TM8620. The TM8800 is currently the most powerful, available in speeds
up to 1.7GHz and built on a brand new
90nm process, while the TM8600 and 8620 top out
at 1.1GHz and use a 130nm process. All three processors feature 128K of L1 cache
memory and a full 1MB of level 2 cache. The TM8620 uses
a smaller chip package for ultra-compact applications, while the TM8800 and TM8600 are identical
in size. As of april 2005, the 130nm have been relegated to EOL orders only, and the company
plans to only continue with its 90nm Efficeon's.
As the Efficeon is intended for
the same mobile applications as the Crusoe, a lot of its development was focused
on increasing performance based on a certain flat amount of
generated heat, instead of designing a processor that was much
faster and correspondingly hotter as would be the case in a typical
desktop processor roadmap.
Transmeta also wished to increase the value of the processor
to mobile system manufacturers by shrinking the amount of
real estate that the processor and its subsystems (north and
south bridge chips) take up on laptop motherboards, where space is obviously
at a premium.
To this end, the
Efficeon actually incorporates all the features of a typical northbridge chip right into
the processor die itself. The AGP interface, memory controller,
a Hypertransport link for connecting to the southbridge chip on
the motherboard, and an interface for PC cards are all built directly
into the processor.
The Efficeon becomes the first processor to completely
incorporate typical northbridge functions, though the Crusoe processor and AMD's
Athlon 64 and Opteron processors came close by building the memory controller
into the die.
The Efficeon, like
the Crusoe processor before it, is not actually an x86-based
processor like Intel's or AMD's products. Instead it uses a different internal
logic, VLIW (Very Long Instruction Word) and uses a software
layer to convert data from x86-designed software like Windows into code the processor can
In effect this software, Transmeta's 'code
morphing' engine, functions as a translator between the CPU and the rest of the
system. This gives the Efficeon the twin advantages of flexibility (since
the translation software can be customized for different applications) and
efficiency since using the VLIW logic requires fewer transistors, and thus uses
less power and generates less heat. Indeed, Transmeta's explanation of
the Efficeon's name is that it will usher in a new 'eon' of efficient
The evolutionary aspect of the Efficeon can be
seen most easily in the essential doubling of its internal capability.
The processor can handle 8x32-bit instructions per cycle as opposed to the Crusoe's 4,
and is capable of handling Intel's SSE and SSE1 instruction sets, which
the Crusoe did not support.
This should result in a substantial performance advantage over
the Crusoe line, especially in multimedia applications and games. The Efficeon now
offers support for DDR SDRAM at 333Mhz, or PC2700. In addition, the Efficeon supports
the use of ECC memory, which potentially opens up the
processor to the server market. The Efficeon has found a home in server
blades where size and heat management are just as essential as they are in the
mobile market. HP currently sells blade systems based
on the Efficeon TM8600 processor.