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New open source GPU is free to all — FuryGPU runs Quake at 60fps, supports modern Windows software
(www.tomshardware.com)
This is a most excellent place for technology news and articles.
There used to be dip switches on some older machines (386/486 era), eventually 'turbo buttons' that accomplished the same thing, toggling would cut the clock speed so older software would be compatible with clock speed. Those turbo buttons were more a 'valet mode' than anything, but it all died out before the Pentium/Athlon era to say the least