450mhz G3 in Beige Desktop

Discussion in 'PowerPC Macs' started by bunnspecial, Jan 9, 2015.

  1. bunnspecial, Jan 9, 2015
    Last edited: Jan 9, 2015

    bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    With my upcoming B&W upgrade project, I'm going to find myself with a spare 450mhz ZIF G3 CPU that I'd really like to install in one of my beige G3 desktops(the one I'm intending to take in and use at work).

    I've been told that this upgrade should work.

    With that said, as per the service manual the processor clock speed needs to be set on the logic board. The service manual seems to indicate that the computer won't even boot if the jumpers are set incorrectly.

    The problem is that the jumper settings in the service manual max out at 300mhz(see attachment below).

    Is there a combination of jumper settings that will allow these computers to run with a 450mhz processor?
     

    Attached Files:

  2. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #2
    You will use a beige G3 at work?! As your main machine? :eek:
     
  3. bunnspecial, Jan 9, 2015
    Last edited: Jan 9, 2015

    bunnspecial thread starter macrumors 603

    bunnspecial

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    #3
    Probably not a main machine, but with a specific purpose-writing exams and other things along those lines.

    Since I'm too cheap to buy current software(and my department doesn't have the money to pay for it), I'm stuck with using an older version of Chemdraw, which is an essential program for me-especially for writing exams.

    The version I have will run under both OS X and OS 9(I have it running in Leopard on my G5) but the OS X version is "stripped down" and it's not as functional in OS X as in OS 9(or even in classic mode under 10.4). Basically, Chemdraw itself works okay in Leopard, but the full ChemOffice suite(most of which I have at least some use for) is strictly OS 9(and, again, Classic doesn't cut it).

    There's also the fact that even the stripped down version of Chemdraw that works in OS X really does not play nicely Office 2008. I had issues when I tried to use the two together, and after researching it a little bit I found out it's a well known enough issue that it even made the Wikipedia page for Office 2008.

    By contrast, Word Perfect Mac 3.5e(which is available as a free download) plays really nicely with Chemdraw. Plus, in a lot of ways, I prefer it to Word, although I am more familiar with Word.

    The combination of writing exams in Wordperfect(a program that no one has anymore) on a computer not connected to the internet really appeals to me. Plus, there's the great Extended II Keyboard that I love typing on.

    Most of the above I could do with something newer like a G4, except that I also have a really nice Laserwriter I'd like to also use that requires a serial port. That pretty much limits me to nothing newer than a beige G3. Of course, I could buy a hardware localtalk-ethernet bridge to use the printer with my G5, or use Apple's software to do the same on a beige G3. If I'm going to do that, though, I might as well just use the G3 directly.

    And, if I get in a pinch with my own printer not working, I save WordPerfect Mac files as a WP Windows file. There are enough folks in the department who still use WP that I can dump the files on a flash drive and print that way if needed(yes, I've already tested that contingency :) ).

    There's also Mac Spartan, which I use occasionally and requires a hardware key that plugs into the ADB port. My G4 upgraded B&W will probably be a better computer for this, but running it on my work computer is appealing also.

    And, no, my G5 as a main machine isn't going anywhere any time soon

    EDIT:

    The tower service manual appears to get me a little bit closer, but still not all the way to 450mhz.
     

    Attached Files:

  4. bunnspecial thread starter macrumors 603

    bunnspecial

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    #5
    Okay, maybe I'm getting somewhere. I found this in the B&W service manual, although the jumper assignments are different...
     

    Attached Files:

  5. bunnspecial thread starter macrumors 603

    bunnspecial

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    #6
    Perfect! Thanks a bunch!

    ----------

    While we're at it-this may be a stupid question and really getting into dangerous territory, but is it possible to overclock the FSB on one of these?

    I know that they are 66mhz, but the 450mhz I'll be installing is coming out of a 100mhz FSB computer and all of the memory I'm using is 100 or 133mhz. If that were in some way possible, it seems that I might see a performance improvement as much if not more so than by upping the processor clock speed.
     
  6. Intell macrumors P6

    Intell

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    #7
    It's possible, but by doing so you start to make the PCI bus run out of spec and become unstable.
     
  7. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
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    #8
    Thanks. I'm actually pretty dependent on the PCI bus in this computer as I'm running a PCI video card, a USB card, and a Firewire card on it. I could live without the USB and Firewire, but don't want to have to deal with the onboard video.

    At least following the guide above, if I raise the FSB to 75mhz it will drop the PCI bus down to 30mhz, but if I go to 83mhz it comes back up to 33mhz.

    I have two of these computers-one to play with and one that I plan to actually use-so I may experiment with the poorer condition one and find a combo of settings that actually works well with the processor before I put it in the good computer.

    Does the same caution about messing with the FSB affecting the PCI bus also apply to the B&W? I see that it can be pushed up to 120mhz, which is really tempting although the default 100mhz is a lot more tolerable than the 66mhz on the beige.

    One of the nice things about having these computers in duplicate or triplicate-and with some in pretty poor condition-is that I can experiment with things like this without too much worry.
     
  8. Intell macrumors P6

    Intell

    Joined:
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    #9
    Messing with the bus speed in any Mac does later the PCI bus speed and effect the stability of them.
     
  9. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
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    #10
    Just wanted to follow up on this...

    As I reported in my thread on the source G3 for this computer, the processor was actually 400mhz and not 450mhz as I had stuck in my head.

    In any case, I went ahead and dropped the 400mhz processor in the beige, and used the jumpers to set the mulitiplier to 6x(396mhz with the FSB at 66mhz).

    The processor read immediately and correctly as 400mhz.

    I also went through my RAM box and found two 128mb low profile sticks, bringing my total RAM up to 512mb.

    With these two upgrades, the system feels a LOT peppier. It's no speed demon, but works great for the jobs I intended it for.

    I do probably need to find a thin fan to stick on the heatsink and cool things down a little bit. I had no instability problems when I was playing with it, but would still feel a lot better if I could get a little bit more airflow over the heatsink(since I don't think these were designed for a processor that fast). If I do that, I may even get brave and overclock it to 466mhz :)

    Again, not ground breaking work, but this was a quick and easy upgrade that made a big difference in the system.
     
  10. Surrat, Jan 21, 2015
    Last edited: Jan 21, 2015

    Surrat macrumors 6502

    Surrat

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    Location:
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    #11
    I went thru a similar process when I first got my powerlogix 1.1ghz g3 upgrade for my beige g3 desktop.

    I ended up using velcro to mount a small fan on the side of the heat sink blowing thru it and towards the PSU intake fan. I had no heat problems after that. There is no room on top the heat sink to mount a fan when you close the upper chassis up.

    After spending a couple years collecting parts to get the best possible beige g3, last revision motherboard, firmware, bordeaux personality card, ultra2 scsi, 56k modem, etc, it ran amazing. Later, I finally located a beige g3 tower, and transplanted the guts into that, which has much more room inside.

    I was never able to locate the high powered VRM that a third party made for the beige motherboard, and was always worried about the 1.1 cpu overloading the standard one. I eventually put a 450mhz g3 in the beige, and my 1.1ghz g3 went into my blue/white tower.
     
  11. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #12
    Thanks for posting your experience with doing this sort of stuff.

    At the end of the day, as much as I love the beige G3 case, I think that the B&W is a better platform for crazy experimenting. It's already ahead of the game with its 100mhz bus, and it's a LOT easier to get more cooling into the case. There's also things like the fact that it gives you four RAM slots, a dedicated bus for the graphics card(effectively AGP 1x even though it's PCI), and three more PCI slots in addition to that. One of my B&Ws is bone stock at 350mhz(I have most of the original stickers and everything else that came with this one, even though they aren't on computer anymore). My "play" computer has a 450mhz G4, and once I get some more airflow over the heatsink I'm going to play with getting pushing it a little bit faster. I'm also trying to get Leopard on it, but that requires me to located the elusive WWDC developer preview to harvest some kexts from it.

    For whatever reason, the G3 minitowers seem scarce around here. I have two desktops, but have never seen a G3 minitower in the flesh. I'd like to have one. If nothing else, being able to use full-height RAM and put a fan on top of the heatsink would be very nice :).
     
  12. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
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    Location:
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    #13
    I tried situating a 60mmx25mm fan in the bottom of the case between the hard drive and processor, but 60mm is too tall to fit. I'm going to experiment a little bit and see if a 40mm fan(and maybe something a little slimmer like 15 or 20mm) will fit in this same space. I hate to use the "brute force" method, but may end up epoxying the fan to the case bottom. These cases really don't leave you a lot of mounting options.

    For the time being, I did put the 60mm fan in the PCI cage, positioned next to one of the vents on the side of the case. Hopefully it will at least get some more air flowing, although I doubt that much will to the heatsink.

    The other downside is that I have this fan hooked up to one of the drive molex connectors, and it runs at full blast all the time, even when the computer is asleep. It's LOUD. The fan I bought(I have a couple of them) is actually the same manufacturer and specifications as the OEM CPU fan on the Quicksilver G4s, but I'm guessing that Apple runs those at a lower voltage as they are nowhere near this loud.

    For the time being, though, I'm pretty pleased with the performance. I have all the PCI bays occupied. I have a graphics card(Rage 128-not the best, but gets the job done), a USB card that was in the computer when I bought it, and now a Firewire card. I spent some time last night playing with Photoshop 7 and it was relatively responses, although Photoshop is one of the applications where a G4 really shines compared to a G3(since it actually takes full advantages of the Altivec FPU).

    I have one last thought...much of the software I was installing last night was on a USB drive. Moving a couple hundred MB over USB 1.1 takes a long time!
     

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