At 13:19 -0500 07/10/2002, Robyn Lyons wrote: >Very handy. I knew what most of the board was, but I didn't know about >J30, the Cache jumper. What does that do? I assume that it >enable/disables the onboard 512K cache. That may prove quite useful. I >think that the onboard cache may be preventing me from clocking my G3 >upgrade past 313MHz.
Correct. If you close the J38 jumper (put a wire across it) it disables the on-board 512K cache in hardware. Most of the G3 upgrades have a software feature to disable the cache, so I'm not sure how useful the jumper really is. You can also buy header strips from JDR Electronics or Digi-Key (.1" pitch) and snip the plastic matrix so that you have a little 2 pin assembly (the strips typically come in 20 - 50 pin lengths). This 2 pin assembly can then be soldered in the J38 position, so that you have pins on which a removable jumper may be installed. This is much more elegant than soldering or desoldering a wire across the bare J38 position. I have only experimented with two G3 upgrade cards, but so far, my experience has been that the nature of the G3 card itself seems to have much more to do with bus speed limitations than any quality of the motherboard. As I mentioned in an earlier post, I have one G3 card that won't do better than 49 MHz no matter what machine it is in. Because it was built to only adjust from 40 - 45 MHz I can't complain too much about that. :-) This is one of the early XLR8 220/110 cards. The positions are there for a switch that will change the range of the bus speed dial from 40 -45 to 45 -50 and so on in 5 MHz increments, the switch simply isn't installed. I've played with another later G3 upgrade that would always do about 58 MHz max bus speed regardless of host machine. Given that both of these cards were tested in some of the same machines, it seems a reasonable conclusion that the CPU card is the limiting factor, not the motherboards. Further supporting that hypothesis, is the fact that my adjustable 604e card in the same machines as above will always do a 61 2/3 bus speed or slightly better. So I doubt that disabling your cache will actually make a difference, but it is possible that it will. 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/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
