The Forbidden and Forgotten UMC Green 486 CPU
4,084UMC’s Green CPU was a unique and impressive feat of engineering. Although it was late to the party, it could run circles around other 486s when it came to clock-for-clock performance. Despite its very promising efficiency, it met an untimely demise due to legal troubles in 1994 and 1995. Join me today as I take an in-depth look at the UMC Green and compare it to a number of CPUs from Intel, AMD and Cyrix. I also push the green well beyond its rated frequency to get a glimpse of what “could have been”.
Big thanks to Andrew (BrassicGamer) from the UK for sending me this CPU. Be sure to check out his blog and YouTube channel:
https://x.com/brassicGamer
http://www.brassicgamer.com/
https://www.youtube.com/@BrassicGamer
Some interesting articles and posts about the UMC legal battle with Intel in the 90s:
https://www.cpushack.com/2012/09/06/intel-vs-the-world-the-338-patent/
https://www.vogons.org/viewtopic.php?t=78628
An article in InfoWorld from October of 1993 about UMC's plans for the CPU:
https://books.google.ca/books?id=-zoEAAAAMBAJ&pg=PA119&lpg=PA119&dq=UMC+Intel+486+lawsuit&source=bl&ots=cMiF3INmdC&sig=XNukgBqjdl0WZ9pNIg1CTMwjOHU&hl=en&sa=X&ei=aUosUM7dBMPUygHutoC4Ag&redir_esc=y#v=onepage&q&f=false
My repair and modification of the Pentium Overdrive:
https://youtu.be/EkAwTPSPhQs
A big comparison of late-model 486 and 486 “upgrade” chips:
https://youtu.be/dQOmSKERPd0
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00:00 Introduction
01:15 About the UMC Green
02:55 It’s All About Efficiency
03:29 Legal Troubles
04:37 Shout Out!
04:56 The Competition and Setup
06:17 Benchmark Results
10:01 Pentium Overdrive Comparison
12:07 Overclocking
13:35 Overclocking Benchmark Results
14:28 Conclusion