This page will list tips and owner feedback regarding using PowerForce G3 design CPU cards in the PowerTower (not PowerTower Pro) and PowerCenter/PowerCenter Pro machines.

" Maybe somebody has already discovered this solution, but I recently uncovered a possible solution to that disturbing "7200 Graphics Accelerator" extension bug that has been plaguing G3 upgrade owners.

Like most Catalyst board (PowerCenter 150) owners, I discovered that the "7200 Graphics Accel." extension generates video garbage with "Powerlogix" type G3 upgrade cards. The prescribed solution has been to disable the extension. Unfortunately, disabling the extension seems to hurt video performance, especially when it comes to menu and page scrolling.

With nobody willing to fix the problem (Apple or Powerlogix-currently the 7200 graphics accelerator extension is the same in Allegro), I have been frustrated by turning off an extension that should be able to run. However, a somewhat elegant solution seems to be turning on virtual memory. Enabling the minimum amount of virtual memory in my memory control panel miraculous stopped all video garbage.

Some people despise virtual memory (et tu Mike), but honestly with 1MB of virtual memory enabled, I can hardly tell the difference in performance. Anyway, I get a sneaky suspicion that virtual memory might make my system a little bit more stable, for what reasons I don't know. But it is unfortunate that companies like Powerlogix aren't willing to investigate or resolve the problems regarding their upgrade cards with such issues/mysteries (motherboard cache, video garbage, etc.). [Not sure these are fixable without possibly having negative performance or other impacts on other Mac models.-Mike]

Anyway the above might make an acceptable solution to some of your readers. It might be prove fantastic with the improved virtual memory scheme in Allegro. Or maybe somebody can see if RamDoubler's virtual memory scheme works even better.

Thank you for diligent crusade in providing the best resource for Mac owners. You make the Mac community feel all the more special.
Alex Lapeyre "

Tips from PowerLogix Tech Support:

" Hey Mike,
I just wanted to fill you in a little on the PowerCenter 150 compatibility. To start off, we have several PowerCenter's here at the Office running PowerForce G3 cards. In fact, we use a 132 and a 150 for testing on RMAs. However, I have run into a few machines in the field with some problems. The symptoms have been as bad as data corruption on the hard drive, but usually just involves consistent crashing. Several factors have seemed to be involved and it is inconsistent across the PowerCurve logic boards (PowerWave [PowerWave is a Tsunami based mb I think-Mike], PowerTower, and PowerCenter(Pro) machines.)

One reason I may not have heard about the problem sooner is that a L2 cache seems to cover up the problem. On affected systems, if the Motherboard cache is left in, the problem is not apparent. However, these machines will always run fine with a 604 card and no cache. Bus speeds seem to also have some effect. I was able to alleviate the problem by running at bus speeds higher than 50. That is not a setting on the cards we ship. However, it is likely to lead us to a solution. Note that only a few (less than ten) cases of this problem have been reported and it may be a small variance on boards from Power which is causing it. In general, the Powercenter machines are the easiest to install the card in and can achieve some of the highest scores.

The best solution for anyone with this problem is to reinstall their Motherboard Cache Dimm. if their computer did not come with a cache dimm, they might consider purchasing one that has a money back guarantee to see if it fixes the problem. They should also try all of our standard troubleshooting steps and contact us for support to try and solve the problem. I have never had a customer return their card to me because it wouldn't work in a Powercenter.

This issue will be updated on our FAQ as soon as we know a little more about it and have a good solution.

Thanks for posting Murat German's note and I hope we can get his working.
Jake Williams
Powerlogix Support "

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