{"id":44690,"date":"2024-09-02T16:14:04","date_gmt":"2024-09-02T20:14:04","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=44690"},"modified":"2024-09-02T16:14:04","modified_gmt":"2024-09-02T20:14:04","slug":"the-apple-iigs-megahertz-myth","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2024\/09\/02\/the-apple-iigs-megahertz-myth\/","title":{"rendered":"The Apple IIGS Megahertz Myth"},"content":{"rendered":"

Dan Vincent<\/a> (via Hacker News<\/a>):<\/p>\n

The Apple II and Commodore 64 with their 6502 and 6510 CPUs clocked at 1 MHz could trade blows with Z80 powered computers running at three times the clock speed. And the IIGS had the 6502’s 16-bit descendant: the 65C816. Steve Wozniak thought Western Design Center had something special with that chip. In a famous interview in the January 1985 issue of Byte magazine<\/a>, Woz said,<\/p>

“[the 65816] should be available soon in an 8 MHz version that will beat the pants off the 68000 in most applications, and in graphics applications it comes pretty close.” End quote. That’s already high praise, but he continues further: “An 8 MHz 65816 is about equivalent to a 16 MHz 68000 in speed, and a 16 MHz 68000 doesn’t exist.”<\/p><\/blockquote>

[…]<\/p>

But that “should” in “should be available” was doing a lot of work. Eighteen months later when the IIGS finally shipped, there was no 8 MHz ‘816.<\/a> It was as nonexistent as Woz’s imaginary 16MHz 68000. 8MHz chips were barely available three years later. What happened?<\/p>

[…]<\/p>

So why were IIGSes with chips rated at 4 MHz not running them at that speed? Why 2.8 MHz? Isn’t that… weirdly specific? Did an 8 MHz machine really get put on ice due to executive meddling? To solve these mysteries I descended into the depths of Usenet, usergroup newsletters, magazines, and interviews. My journey took me through a world of development Hell, problematic yields, and CPU cycle quirks.<\/p><\/blockquote>\n\n

Dave Haynie<\/a>:<\/p>\n

Way back in ’85, a 4MHz ’816 cost noticably more than\nan 8MHz 68000. Things are going to be even more skewed now.<\/p><\/blockquote>","protected":false},"excerpt":{"rendered":"

Dan Vincent (via Hacker News): The Apple II and Commodore 64 with their 6502 and 6510 CPUs clocked at 1 MHz could trade blows with Z80 powered computers running at three times the clock speed. And the IIGS had the 6502’s 16-bit descendant: the 65C816. Steve Wozniak thought Western Design Center had something special with […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"apple_news_api_created_at":"2024-09-02T20:14:07Z","apple_news_api_id":"54a70c25-0b04-423a-b3d0-f668a581ebae","apple_news_api_modified_at":"2024-09-02T20:14:07Z","apple_news_api_revision":"AAAAAAAAAAD\/\/\/\/\/\/\/\/\/\/w==","apple_news_api_share_url":"https:\/\/apple.news\/AVKcMJQsEQjqz0PZopYHrrg","apple_news_coverimage":0,"apple_news_coverimage_caption":"","apple_news_is_hidden":false,"apple_news_is_paid":false,"apple_news_is_preview":false,"apple_news_is_sponsored":false,"apple_news_maturity_rating":"","apple_news_metadata":"\"\"","apple_news_pullquote":"","apple_news_pullquote_position":"","apple_news_slug":"","apple_news_sections":"\"\"","apple_news_suppress_video_url":false,"apple_news_use_image_component":false,"footnotes":""},"categories":[2],"tags":[401,406,2639,295,30,260,779,1535],"class_list":["post-44690","post","type-post","status-publish","format-standard","hentry","category-technology","tag-680x0","tag-appleii","tag-apple-iigs","tag-history","tag-mac","tag-processors","tag-steve-wozniak","tag-tony-fadell"],"apple_news_notices":[],"_links":{"self":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/44690","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/comments?post=44690"}],"version-history":[{"count":1,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/44690\/revisions"}],"predecessor-version":[{"id":44691,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/posts\/44690\/revisions\/44691"}],"wp:attachment":[{"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/media?parent=44690"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/categories?post=44690"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mjtsai.com\/blog\/wp-json\/wp\/v2\/tags?post=44690"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}