

CPU DB: Recording Microprocessor History - CowboyRobot
http://queue.acm.org/detail.cfm?id=2181798

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DiabloD3
I'd like to see a database that contains stuff like what C #defines are often
used with it, what endian it is (or which OSes typically use which endian for
those CPUs that are biendian), and the same for #defines for OSes.

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frou_dh
The other day I did a braindump of all the computers and handhelds I've owned
so far, and their basic specs, before I forgot. I plan to maintain the list
because it's fun to look back on :)

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joe_bleau
Note the relative energy/op for the Pentiums in figures 10 and 11.

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miahi
The Pentium architecture pops up from time to time (after the Netburst
architecture Intel rolled back closer to the original Pentium architecture,
and now Larrabee/MIC uses the same Pentium cores). At that time it was
efficient because the memory clock was not very different from the CPU clock
(6x-10x ratio) - the memory access did not cost a lot of CPU cycles, so the
CPU had a decent performance without a big on-die cache. At higher clocks
(more than 1GHz, ratio >10x) the Pentium architecture (Pentium III at that
time) showed its age and had to be replaced (with the not-so-good Netburst).

Right now the CPU/memory ratio is higher (20x and more), so the CPUs require
big caches to compensate. The CPU cache has a huge transistor count, being
SRAM (Static RAM, very low latency). Every SRAM bit is implemented with 6
transistors, so for 1MB of cache you need ~50 million transistors.

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ableal
Another way of looking at it - which I believe was not covered in the article
- is observing chip areas.

If you look, top-of-the-line server chips (Xeons, etc.) pretty consistently
hit 300 mm2. On the other hand, mid-range desktop chips usually are about 100
mm2. Besides marketing, pricing also has to do with process yield, which is
not linear: 3x area is more than 3x more expensive.

What to do with that area? Given the shrinkage that allows multiple CPU cores,
the answer that gives best price-performance is cache, after the first 4 or 6
CPU cores ...

