At 16:24 -0800 01/29/2003, Will Schou wrote: >> From: <[EMAIL PROTECTED]> >> Date: Thu, 30 Jan 2003 07:28:25 +0900 >> >> Well I thought I'd made it clear enough in my first post, but >> obviously most >> people only read the first few lines.
>You are very right about most people not reading far enough to really >know what the issues etc are ;-) >I checked this out with some interest. If I'm correct selecting a >system bus speed on the Sonnet G4 800 is done by replacing the crystal >oscillator which is done by removing it from the board and replacing it >with another of a different speed. It is inside a small very small >metal can. This is done with a soldering iron shudder ;-) Will, you are correct. The bus speed is adjusted by physically trading the oscillator. There is a web page by one of the denizens of xlr8yourmac.com's forums in which he worked out resistor combinations to change the bus multipliers. Since the top multiplier of the G4 (7455) is 16X and the 800 MHz version of the card already uses 16X, this isn't very productive. It might be handy for the 700 MHz card though. Now one interesting item in this bus multiplier work, is that the resistor adjustments apparently go above 16X, the chip simply doesn't support it. But if Sonnet makes some 800 MHz upgrades with a later revision of the G4 chip, then those higher multipliers might be usable. Anyway, in order to increase the bus speed the oscillator needs to be desoldered. It only has four pins. If you're willing to take the big leap, this needn't be too scary. The easiest way is to snip the pins at the base of the oscillator, lift off the oscillator, and then remove teh pins one at a time with soldering pencil and tweezers. The problem with this method is that you can't change your mind after you've snipped the first pin. Anyway, once the pins are removed you can install a socket and then install any speed oscillator, with no fuss, in the socket. I'm a little doubtful about the previous sentence, because I worry about using a socket with oscillators that are 50 and 60 MHz in speed, but I don't have an experiential reason to believe that it will work poorly. Anyway, one could pick up a socket (digi-key has half-size metal can sockets) and an assortment of oscillators and go to town on overclocking the thing. 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:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
