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PC motherboards without a 14.31818 MHz crystal

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    PC motherboards without a 14.31818 MHz crystal

    On an Asus P8Z68-M PRO motherboard from, I could not find a 14.31818 MHz crystal anywhere; all of the crystals except the RTC crystal were marked with MHz integers.
    You may know this, but 14.31818 MHz was used in the original IBM PC (4.772766 MHz for the 5 MHz-rated CPU (divide by 3) and (on a video card) 3.579545 MHz for NTSC colourburst (divide by 4).
    So therefore (in my theory), it is easier to generate required clock frequencies (including the 100 MHz reference clock for PCI Express) with a crystal of a MHz integer than a 14.31818 MHz crystal - are all new PC motherboards going this way?
    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

    #2
    Re: PC motherboards without a 14.31818 MHz crystal

    it's down to the PLL/clock generator they choose.

    i'm surprised they arent trying to use the 32KHz crystal!

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      #3
      Re: PC motherboards without a 14.31818 MHz crystal

      Looks like that's the standard HPET granularity frequency.
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      Last edited by RJARRRPCGP; 05-16-2019, 02:19 PM.
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        #4
        Re: PC motherboards without a 14.31818 MHz crystal

        It's been a long time since computers had to use weird clock frequencies to get other frequencies by division or multiplication.

        Why would they use something chosen because it's ntsc subcarrier.. ntsc is not the only thing in the world.
        See https://en.wikipedia.org/wiki/Crysta...or_frequencies for common frequencies.


        You may still find some weird clocks for UART (serial ports) or on sound cards...

        You're more likely to find 12 Mhz with USB

        @RJARRRPCGP that varies, for example on my system it's 3.418 Mhz

        Comment


          #5
          Re: PC motherboards without a 14.31818 MHz crystal

          Originally posted by mariushm View Post
          It's been a long time since computers had to use weird clock frequencies to get other frequencies by division or multiplication.

          Why would they use something chosen because it's ntsc subcarrier.. ntsc is not the only thing in the world.
          See https://en.wikipedia.org/wiki/Crysta...or_frequencies for common frequencies.


          You may still find some weird clocks for UART (serial ports) or on sound cards...

          You're more likely to find 12 Mhz with USB

          @RJARRRPCGP that varies, for example on my system it's 3.418 Mhz
          I heard that the 3 Mhz one isn't HPET.

          See this thread:

          https://www.badcaps.net/forum/showthread.php?t=75378
          Last edited by RJARRRPCGP; 05-16-2019, 04:09 PM.
          ASRock B550 PG Velocita

          Ryzen 9 "Vermeer" 5900X

          16 GB AData XPG Spectrix D41

          Sapphire Nitro+ Radeon RX 6750 XT

          eVGA Supernova G3 750W

          Western Digital Black SN850 1TB NVMe SSD

          Alienware AW3423DWF OLED




          "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

          "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

          "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

          "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

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