> From: Jeff Walther <[EMAIL PROTECTED]> > Date: Sun, 12 Jan 2003 20:28:04 -0600 > At 17:09 -0800 01/12/2003, Will Schou wrote: > Finally Powerlogix is going to be selling soon new upgrades for our > machines! > PowerLogix is also proud to announce the highest performance for older > > G4, the economical PowerMac G3 800 ZIF features an IBM 750FX running > at 800MHz with 512K of cache running at a blazing 800MHz. Its great > > > The above G3 Zif will likely > fit the Zif carrier cards made by several companies, XLR8 being the > most common but also Powerloix and Newertech made them. However unless > someone comes up with some tricks I don't believe they can run at full > speed in the carrier card looks to me that 700mhz might be the limit so > the cpu daughter card below at the same price is likely the way to go . > > I think folks are saying that 700 MHz may be the top available because > that's as high as one can get with the adjustments available on the > carrier card. But there may be some flaws in that reasoning. Some of > my reasoning to follow may be flawed as well, as I don't know all the > ins and outs, but in one possible universe which may be this one... > > The 700 MHz limit is being arrived at by looking at the bus multiplier > settings available on the ZIF carriers and multiplying it by the top > bus speeds available. However, the multiplier settings are just > arrived at by taking four pins and either tieing them to ground or > voltage in various arrangements. The standard ZIF card has four pins > which connect to the ZIF carrier's pins and read that arrangement and > interpret it as a bus multiplier (PLL) setting. > > The 750FX ZIF may interpret those arrangements of the four pins in a > different manner than older ZIFs, allowing higher bus multiplier > settings (750FX goes up to 20X). There's no reason that "on, off, off, > on" must mean 10X for all ZIFs. It could mean 10X for one model of ZIF > and 16X for a different model depending on how they're wired. I made > that example up. I don't know what the setting is for 10X. > > So, with clever interpretation of the PLL pins, the 750FX could go up > to its maximum bus multiplier settings on existing ZIF Carriers. It > depends on what PowerLogix did. > > Second, ZIF carriers only have four PLL pins. The 750FX has five PLL > pins. So no matter how you slice it, existing ZIF carriers are short > one PLL pin for the 750FX ZIF card. I don't know what PowerLogix will > do about this. > > Third, some existing ZIF cards ignore the carrier card PLL settings > and have their own on-board jumpers or switches for setting the bus > multiplier. This is probably the most logical route for Powerlogix to > take, given the four pin/five pin incongruency. > > So, my guess is that the bus multiplier will be set using pins on the > ZIF module and that the bus multiplier (PLL) settings on the ZIF > carrier card (and the Beige G3 motherboard) will be ignored by the > PowerLogix 750FX ZIF.
Using the new Zif cards in the carrier card is wishful thinking on my part. I know they will fit since the Beige G3 uses the same pin settings for there built in Zif. Powerlogix isn't marketing them for this use. At least at this time. Both cards are the same price so no advantage for the end user....except the XLR8 carrier card has a lot more settings on it then Powerlogix usually provides. Most Powerlogix cards only provide major number bus settings ie" 45,50,55,60 with nothing in between. XLR8 cards provide every number bus settings ie, 50, 51 52 etc with some bus numbers even letting you add .6 to the numbers! now that is fine tuning and makes a difference on some machine setups. > Fourth, the 750FX has the ability to reset it's bus multiplier with > software. Some of you may have seen the articles on XLR8yourmac.com > about over-clocking the iBook with a software utility. The same would > be possible with PowerLogix's 750FX ZIF, assuming that PowerLogix > provides such a software utility. Powerlogix has just announced this for the Pismo powerbook! > " PowerLogix is also proud to announce the first ever > software-controlled, variable speed CPU upgrade. Available for the > PowerBook G3 Pismo (aka Firewire or PowerBook G3 2000), the Blue Chip > G3 800 Pismo can be adjusted instantly 'on the fly' (i.e., no reboot > required) to a lower clock speed in order to extend battery life. > PowerLogix includes an easy to use software utility for this purpose. > Tests show that up to 30 minutes of additional battery life can be > obtained by lowering the clock speed, which can be very useful in > certain situations, such as long plane flights. In many cases, such as > spreadsheet or word processing, sheer clock speed takes a back seat to > battery life, and in the Blue Chip G3 800 Pismo offers the best of > both worlds. The clock speed is user adjustable from 300 to 800 MHz. > The Blue Chip G3 800 also features the IBM 750FX, with 512K of L2 > cache at 800MHz." > All in all, some very exciting upgrades, though I'm not sure how well > they compare to the Sonnet G4/800 for us PowerSurge users. True, an > 800 MHz G3 should give about the same performance as an 800 MHz G4 for > non-Altivec applications, but the caches are very different between > the two upgrades. I'm guessing there will soon be benchmarks ran comparing the Sonnet and Powerlogix products. I've not yet found a OSX bench marking app which gives me figures I can understand /compare with OS 8/9 benchmarks. > The G4/800 has a 256K L2 cache on the chip which runs at CPU core > speed, and a 1 MB L3 cache which runs at 200 MHz. The 750FX (G3/800) > has a 512K L2 cache on the chip which runs at the CPU core speed and > no L3 cache. So who wins? 256K at 800 MHz helped by 1 MB at 200 MHz > vs. 512K at 800 MHz with no helper. The G4/800 isn't that much more > expensive depending on what the street prices do. Yes, but the Powerlogix will likely be clockable...so I'm guessing it may well run 850 to maybe close to 900mhz ( I hope ! ) This may well help make up for the lack of L3 cache? The older G3 cpu's could be counted on for 10-15 % over-clocking in most cases! I have no info on the new chips in this regard. > Finally, the 750FX is supposed to go to 1 GHz and it does support a > 20X multiplier, so we could see a (50 MHz X 20) 1 GHz upgrade for our > machines without too much effort on PowerLogix's part, now that they > have the basic design going. > > Jeff Walther Thank you for sharing your superior knowledge on hardware details! I'm still pretty happy with my 500mhz G3 running at 550 mhz. It is more then fast enough in OS 9.1 in fact scrolling drives me nuts as it is too fast! I am know living in OSX jaguar land where it works great but is more like 300-350mhz was in OS 9.x . Plenty fine but OSX now has enough apps that I can now do Video work which before I had to do on a PC. OS 9.x just didn't have the apps. So someday when the price is right I will want one of these fast upgrades. While the new Apple machines are pretty they are too much money. I have also read reports that starting with the iMacs life is likely going to be shorter for macs in general. The iMacs which are newer then our machines are starting to need expensive repairs which require parts only available from Apple . I read about this in a Smalldog news letter. They said $300-350. repairs were becoming common and they wouldn't be surprised if Apple discontinues parts for the first iMacs next year! So it seems to me the new Macs are more disposable like nearly everything being sold these days. later Will S -- SuperMacs is sponsored by <http://lowendmac.com/> and... 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