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hoi polloi

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  1. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    Did you have any luck with this? I found a dual 800MHz quicksilver CPU card to play with. I swapped in a couple 7455B chips and it's working now at 1.2GHz with the 2MB L3 cache. The 7455B chips are much better than the original 7450. They're both faster and cooler at a lower voltage. This board has a microcontroller chip on it. Does anyone know what it does?
  2. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    I was able to make some progress on this. It is possible to enable the L3 cache after boot. This is a 733MHz 1MB L3 DA card that I swapped the CPU and cache chips, and removed the flash chip so that it would boot:
  3. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    If you can read them, can you also write them? The best result so far is the one in the first post, which is using the flash chip from a 1.25 MDD single with 1MB. As you can see, it runs at 6x, and I've been able to get this card to work at 1.6GHz with the original 1MB cache chips. That takes a lot more power than 1.4GHz though, so that's where I've been running it. If we can figure this out, ideally I would like to be able to transplant the CPU and cache chips from a MDD card and run a single at 5x or 6x with 2MB. I wonder what OWC would say if we asked them about the details of their aftermarket CPU cards.
  4. What is the latest on this? Were you able to repair or replace the PSU?
  5. Do all of those ports work? The firewire chip looks a bit corroded. At least it looks like you got a nice CPU upgrade with it! Which one is it?
  6. Could it be the power supply?
  7. hoi polloi

    Cube VRM - bump up components

    What do you mean by 'regulator' on the VRM? The VRM is a DC-DC converter that takes 28v in and puts out 3.3, 5 and 12v. Usually a 'regulator' does this same thing for low power applications because it's inefficient (heat). I've replaced these VRM FETs with new ones a few times. There are better parts out now that can handle more current with similar gate charge. I've done this to repair a dead VRM and also to use a 7455 CPU upgrade supplied by the 5v section of the VRM.
  8. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    The chip is a little 8-pin surface mount part marked 3402W. Just about any G4 CPU card with cache chips will have one. Even the 350MHz 7400 cards. I've had some luck transplanting these chips, but I get some weird behavior. I installed some 2MB cache chips, thinking it would work with the 1MB flash firmware but only show 1MB; it started to boot and spewed a bunch of weird error messages. I tried a flash chip from a 2MB dual card and got different error messages. With no flash chip it will boot with L3 disabled. Did apple ever make a fast single CPU with 2MB L3? Or any single with 2MB? Maybe with enough of these chips and a reader I could work out a pattern. I wasn't able to find any documentation on them from motorola (NXP). Does anyone here have a TL866?
  9. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    I don't suppose anyone here is able to flash these chips? It's frustrating to be able to re-solder 600 connections and then get stopped by software. This is the same issue with using the 7448... I discovered that if I remove the flash chip the machine will boot without L3 enabled. Is there a way then to enable the L3 after boot? With Reggie, if I try to set the L3CR register this way I get an error.
  10. hoi polloi

    How to set L3CR Cache for DIY G4 CPU Upgrade

    Thank you for replying; that is some great info! So how are you reading/writing that flash chip?
  11. I've been tinkering with a BGA-swapped CPU card and I've had difficulty getting it to run at speed because of the L3 cache ratio. The original 733MHz CPU works with a 4:1 ratio, but the 1400MHz chip needs 6:1. Does anyone know how to set the L3CR register at or before boot time? I suspect there is a way to do this in open firmware with a script of some sort. Alternatively, is there a way to re-program the flash chip on the CPU card?
  12. hoi polloi


  13. hoi polloi

    CPU upgrades for Cube

    OSX definitely knows when it has dual CPUs. Even if a particular app isn't written for it, I've had better overall productivity on duals because I usually have multiple programs going. Here is one of the comparisons I remember seeing: https://barefeats.com/pm05.html He has done a few similar comparisons, including some with Cube specific upgrade CPUs. In this one you can see that in most cases the dual 533 beats a single 933. Of course a dual 1GHz is faster, but that's not too realistic in a Cube. The best CPUs I've seen in a Cube are the Powerlogix/Newer Tech dual 7447 or 7448 boards that get their power straight from the 28v input and don't stress the VRM.
  14. hoi polloi

    Lower Geekbench score after installing a 7800GS

    Pull up activity monitor or run top, etc. It should be pretty clear what's going on. As I said, geekbench is not a good benchmarking tool. Anything, and I mean any--thing, else running will lower the score. Try safe booting, for example...