Archive for December, 2011

Stub 0.97b released

Just bugfixes with this release; removed any sane attempt to detect 80C8x CPUs because there’s no way to distinguish them from 808x CPUs made after 1981; also patched AMD 386SX detection code because it was false-positiving all the time.  Download filename is the same.

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Some answers

While the main TOPBENCH full tool is not yet available, the helpful folks over at the Vintage Computer Forum have been helping me test the base metric code, and already some decades-old questions for me have been answered.  Comparing (by hand, for now) over 50 submissions, I’ve been able to determine:

  • Yes, a 386DX-40 was faster than a 486sx-25.  (Who was faster was claimed by both sides at the same time, so it’s nice to finally know the truth.)
  • A stock IBM PCjr is roughly half the speed of an original IBM PC.  But you can double the PCjr’s speed by getting a memory expansion (the expanded memory does not have wait states), and you can double it further by replacing the 8088 with an NEC V20 CPU, and upgrading the crystal so that the system runs at 8MHz.  So a fully-modded PCjr is twice as fast as a PC.  (Wouldn’t it be incredible if we could do that with modern machines?  $20 in parts and an afternoon, and your 3GHz Core i7 could now suddenly run at 6GHz?)
  • Forgetting to turn the cache on in a 386DX machine could cut the system’s speed in half.
  • Replacing CGA with VGA could, with fast VGA cards, increase graphics speed by 50%.

I hope to have an alpha version of the full tool ready in the next few weeks.

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