At 19:05 -0500 11/09/2002, J J wrote: Jeff Walther wrote: >>"It's moot with the G4/800 anyway. You can't >>adjust the bus speed >>without soldering to replace the oscillator. >>
>So, are you saying that the new G4 800 will let >our buses go say 100Mhz (maybe). Or maybe a better >question would be - How fast will the bus be after >installing a G4 800 processor in it? The Sonnet G4/800 is set to run with a 50 MHz bus. That is how it gets an 800 MHz CPU speed. The MPC7455 chip (G4 chip) has a maximum bus multiplier of 16X. So 16 X 50 MHz = 800 MHz. If one could easily adjust the bus speed, one might get that up higher. For example, 55 MHz X 16 = 880 MHz. However, who knows if the MPC7455 will tolerate running at speeds higher than 800 MHz? There was a news item on XLR8yourmac.com in which a fellow claimed to have done a 60 MHz X 16 = 960 MHz with the Sonnet card. Assuming it wasn't made up that would be pretty cool. I don't know how high a bus speed the Sonnet card could manage. The max bus speed has more to do with printed circuit board design and quality and little or nothing to do with which CPU is on board. Most of the CPU card companies probably don't worry about optimizing the design after they manage 50 MHz, because that is the nominal maximum anyway. Tthe method behind this modification is to desolder the oscillator (crystal?) and replace it with one with a higher speed. Most folks aren't going to want to do that. However, I notice that the oscillator is a half-size metal can. I know the small company Output Enablers used to sell a device called a Chip Clip which would disable a full-size metal can oscillator and replace its signal with a user installed oscillator. This might be a nice application for their old product, assuming they ever made one for half-size metal cans. Perhaps I'll email them about that... You can find the link to Output Enablers at "The Clock Chipping Home Page" which is maintained by Marc Schrier. You should be able to find a link to TCCHP in the links page at XLR8yourmac.com. Jeff Walther -- SuperMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:supermacs@;mail.maclaunch.com> To unsubscribe, email: <mailto:supermacs-off@;mail.maclaunch.com> For digest mode, email: <mailto:supermacs-digest@;mail.maclaunch.com> Subscription questions: <mailto:listmom@;lemlists.com> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
