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Apologies if this isn't the right place to ask but I'm pretty stuck at this point. I've been searching all day and no one seems to have the information that I need.

What I'm looking for are the average access speeds for a few different kinds of memory:

  • CPU Registers
  • CPU Caches
  • Primary Memories (RAM)
  • Flash Memories
  • Hard disks (which I think are ~9ms)
  • DVDs

All I've been able to find thus far are transfer rates, not access times. Ideally if someone could just point me in the right direction, like a link to wiki that I've obviously missed that would be awesome :)

Thanks in advance.

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FYI, RAM-type memory this is pretty easy, as they tend to run on standard bus speeds. But DVDs/Flash/Hard Drives will be all over the place - they are highly dependant on the individual device - HDD's for example can have an average seek time of between about 3 and 15ms (from max performance server drives to impact-resistant mobile drives), and an average latency of between 2 and 6ms (depending of rotational speed). So a HDD could have an average access time anywhere between ~5 and 21ms. – DMA57361♦ Sep 13 '10 at 9:17
Indeed, but as long as I can get a ball park I'm not that worried :) – mispecialist Sep 13 '10 at 23:43
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This is what I found out so far

  • DRAM - 60 ns (35ns cycle time and 25ns latency time).

  • SDRAM - 10 ns.

alt text

Image from Wikipedia

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Nice, I can't believed I missed this, wiki is more or less the only place I've found useful so far. Thanks :) – mispecialist Sep 13 '10 at 23:44
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