Intelligent RAM

1
Intelligent RAM

• A microprocessor into a memory chip
• Dave Patterson, Berkeley, 1997

2
Context

• Distinct manufacturing lines
• Processor-Memory performance gap
• Memory wall
• Awkwardness of DRAM chips

Time to unify logic and memory
3
Advantages

• Higher bandwidth and lower latency
• Less distance (no bus) and less complexity
• Less energy consumption
• Less heat, better performance
• Costs efficient
• Save board space

4
Disadvantages

• Consequences on cost/bit and refresh rate
• Manufacturing challenges
• Reduce interchangeability
• ILP trade-off

5
VIRAM
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6
Microarchitecture
7
Results

• Multiple operations can execute concurrently
  across parallel lanes
• High performance
• but
• Not efficient with short vectors
• Useless for non-vectorizable parallelism

8
Conclusion

• VIRAM / DIVA not real successes
• but implications in embedded systems
• Intel Through Silicon Vias, personal
  technology to connect DRAM and processor
• First step to IRAM ?