EDEN vs CRUSOE CPU Comparison Presentation

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EDEN vs CRUSOE CPU Comparison Presentation

• Author Jack Ho

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Overview

• Brief examination of the architecture and
  technology underlying these two low power CPU
  families
• Benefits and disadvantages of each architecture
• Comparison of Crusoe vs Eden
• Companies behind these two products

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Transmeta Crusoe I

• Low power design achieved by eliminating the
  complex transistor hardware necessary to support
  x86 ISA
• Special Code Morphing Software to translate x86
  instructions into native Crusoe instructions
• 64K L1 instruction cache (8-way associative), 64K
  L1 data cache (16-way associative), 512K L2
  write-back cache (4-way associative)
• Unified 256 entry TLB (4-way associative) to
  enhance cache hits

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Transmeta Crusoe II

• Integrated north-bridge to handle memory and PCI
  interface
• Code morphing software is built on a 2MB ROM
• Typical power consumption 1W (TM5800 800MHz)
• Maximum power consumption of 6W (TM5800 800MHz)

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VIA Eden I

• Low power design achieved by reducing transistor
  count through optimization of the hardware for
  the most commonly used x86 instructions while
  off-loading the infrequently used instructions to
  software
• 64K L1 instruction cache (4-way associative), 64K
  L1 data cache (4-way associative), and 64K L2
  victim cache (4-way associative)
• Separate, dedicated 128 entry TLB (8-way
  associative) for both instruction and data cache
  to maximize cache performance

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VIA Eden II

• Typical power consumption 3.2W (Via Eden 667MHz)
• Maximum power consumption of 6W (Via Eden 667MHz)
• Major components (caches, tags, TLBs) are turned
  on and off on a clock-by-clock basis based on
  usage to improve power management

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Crusoe Advantages

• Code morphing software allows the Crusoe CPUs to
  translate different ISAs, not just x86
• Integrated north-bridge reduces PCB space
  requirements
• Extremely low typical power consumption allows
  for superior battery-life in applications where a
  constant power supply source is not available

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Eden Advantages

• Optimization of the hardware for the most
  frequently used x86 instructions allows for
  top-notch performance
• Typically, only a few instructions are used 90
  of the time (Instructions such as ALU store, etc.
  are optimized to run in 1 clock cycle)
• Eden cache is unique in that the L1 and L2 are
  exclusive rather than inclusive (This means that
  there is no repetition of data in the two caches,
  effectively making 192K L1 cache available)
• Most of the actual system performance gained from
  cache is the result of L1 cache hits (Combined
  with the dedicated TLB for data and instruction
  cache, performance is greatly enhanced)

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Crusoe Disadvantages

• Code morphing software, surprisingly, is also the
  major disadvantage
• Code morphing software is actually loaded into
  system memory at boot-up (taking up 2MB of system
  memory plus an additional 6-14MB for caching)
• All instructions are intercepted by this software
  and translated into native code before being
  passed to the CPU
• The problem with this method is that it can
  actually take up to 6 times more system memory to
  run the same code on a native x86 based CPU
• Thus 64MB System Ram is effectively 8-9MB Ram
  (64MB System 2MB Code Morph 6 to 14MB
  cache) / 6
• Resulting in a need for more frequent access to
  disk based virtual memory

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Eden Disadvanteges

• Need for both a North-bridge and south-bridge
  increases PCB space requirements
• Typical power consumption of 3.2W does not make
  it a viable option for mobile, battery-based
  devices
• FPU runs at half the speed of CPU core

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Eden vs Crusoe I

• Real-life power consumption comparison of
  complete platforms using VIA Eden 400MHz, Crusoe
  TM5600 600MHz, and Intel Ultra Low Power Celeron
  400MHz

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Eden vs Crusoe II

• Real-life comparisons of complete system
  platforms using NS Geode GX1 233MHz, Crusoe
  TM5600 600MHz, Eden 400MHz, and Eden 533MHz

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Eden vs Crusoe III

• From a cost and performance standpoint, the Eden
  CPUs are able to offer better performance at
  about 2/3 the cost of Crusoe CPUs
• Both CPUs are not great at graphics intensive or
  FPU intensive arenas
• Both can operate in a fan-less environment
• Both offer long product life cycles (4 years) for
  the embedded market

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Transmeta Corporation

• Company founded in 1996
• Introduced first Crusoe CPU in 2000
• 2001 Revenue of 35.6 mil
• 2001 Net Loss of 171.3 mil
• 2002 Revenue of 24.2 mil
• 2002 Net Loss of 110 mil

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VIA Technologies

• Founded in 1987
• Developer of PC core logic chipsets,
  microprocessors, and multimedia and communication
  chips
• 2001 Revenue of 986.9 mil
• 2001 Net Income of 153.2 mil
• 2002 Revenue of 725.2 mil
• 2002 Net Income of 44.7 mil

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Conclusion

• Eden and Crusoe are both outstanding low power
  CPUs with their own markets (Eden provides better
  performance and cost value, while Crusoe provides
  extremely low typical power consumption)
• Acrosser does not focus on battery operated
  devices, thus Eden CPUs offer the best value for
  our customers
• The solid financial history of VIA ensures that
  their products will continue to progress with
  innovative developments and existing CPUs can
  count on long product life cycle support
• Transmetas poor financial history (they have
  never achieved profitability since their
  founding) makes long term cooperation a more
  risky venture for embedded platform providers who
  rely on solid product life cycles