Re: Moravec's estimates?

From: Brian Atkins (
Date: Mon Apr 09 2001 - 18:52:23 MDT

The Blue Gene chips will have 16MB RAM on-die last I heard. Now that is
going to be shared I guess by the 32 CPUs that will be on each die, so it
isn't a lot. But it should have fantastic stream numbers. The total machine
should have around 500GB of RAM from what I calculate.

Hard to believe we are already closing in on 18 months since Blue Gene was

James Rogers wrote:
> At 05:18 PM 4/9/2001 -0500, Jimmy Wales wrote:
> >One potential problem with Moravec's estimates (indeed, any estimates
> >based on MIPS) is that even if we achieve human-level MIPs in 5-20
> >years, we've only got one piece of the puzzle. One other major component
> >is having enough memory (RAM). And so we need to look at Moore's Law
> >type considerations for RAM/$$$$ as well.
> RAM/$ isn't the real problem, nor is addressability (a reasonable AI
> implementation could probably be done in a full 64-bit address
> space). The problem is memory bandwidth, which is already becoming a
> serious problem for ordinary computer applications.
> Let's suppose you have a computer that has enough memory to store a human
> level AI and some roughly equivalent level of computational power, both of
> which are very easy to foresee in the near future because they are growing
> quickly technologically. The problem is that we are a very long ways away
> technologically from being able to feed a memory that large into a
> processor that fast; improvements in memory bandwidth have been very slow
> in coming and it doesn't look like this situation will change.
> If you hang out on the scientific computing lists, you already see this
> limitation being hit pretty hard. For problems that have substantial data
> sets, the computational speed is limited to the speed of the memory bus,
> not the theoretical computational throughput of the processor. For these
> apps, stream benchmarks (memory throughput) are the hardware benchmarks of
> choice, not FLOPS or MHz. (Note that for these reasons the Apple G4
> processor is considered a joke in the high performance computing circles
> compared to Intel and AMD processors, despite Apple's marketing campaign
> suggesting that they give "supercomputer" performance).
> -James Rogers

Brian Atkins
Director, Singularity Institute for Artificial Intelligence

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