I was getting so many mails on the issues of the PowerForce G3 card running in a 7500 (and similar systems) that I felt a permanent page was in order. Here are the latest tips and feedback :

Railgun Runs 50MHz bus in 7500: Eugene Kuo wrote a mail describing his surprise that his new Railgun runs 50MHz bus speeds in his 7500 (with no motherboard cache dimm). From his letter it appears his Railgun is a clone of the latest PowerJolt Mactell model that features 50+MHz bus speeds. Interesting too that he did not need a fast cache dimm installed, as most 7500 owners reported report is required with most PowerForce design cards.

Update: Check SCSI Disk Termination!

" Mike,
Just a quick update to my previous comments (via your Card feedback page) on my Val4 7500 and it's chronic instability after installing a PF 221/110 card.

I battled this beast for weeks, panicked that the dreaded Val4 problems would kill my 7500's future. I finally decided with some help from PowerLogix tech "Jacob" that the problems were disk/SCSI related.

To cut a long story short my IBM-OEM 1GB drive shipped from Apple 3 years ago without bus-termination, yes it IS the last device in the chain and I won't tell you what I wished on Cupertino's QA personnel that night. I found the drive specs on an IBM site and enabled the "active termination" setting.

VOILA! a more stable Mac running the PF card at 300/150 than it has EVER been before. Hope this may help some other poor schmuck.
your fan
Tim"

" Hello Mike,
I have a follow-up report for your G3/7500 upgrade page.

My 7500/Powerlogix 220/512k runs great at 315mhz/45bus with an old Techworks cache installed. This cache supposedly only works in a 7200, but might be found for as little as $10. (That was not the original story from Techwork's 'outrageous customer service'...)

The same cache never worked in the same 7500/same motherboard running either the original 601/100 CPU or a Powertools 604/150 (from S900 UMAX). It used to crash, cough sputter, etc... Other caches that never worked included the updated Viking 512k and the Powerlogix 1mg (non-ultra). BLOL accepted the 1mg in return.

It is still true that if i remove the L2 cache, the G3 will not boot, but the 604/150 will. The G3/No L2 cache freezes with a gray screen prior to the HappyMac/flashing "?". Reinstall the Cache and it works fine.

My machine was purchased 8/11/95, the first week 7500s were available.

Ted Anderson"

"Hi Mike,
after reading your report regarding the PowerForce G3 220/110, 512 kB processor upgrade card, I immediately ordered it from BottomLine. Today, 3 weeks later, I finally received my PowerForce card.

Now my PowerMac 7500 is really flying and the card runs rock solid @ 315/126 MHz.

Thank you very much for your recommendation,
Michael A. Byczkowski"

"Hey again Mike,
There _is_too_ an issue somewhere between the 7500 and the Powerlogix 220/512k G3.

I mailed you a few wks ago about my 7500. I searched around for a replacement motherboard, and took it in. Today (thurs), I just got mine back from the shop, again, a different shop even (ICNi in L.A.) and they got my machine (with the old motherboard) to work with the 220/512k only if a L2 cache dimm is installed in the L2 slot. go figure. This is the same machine that refuses to boot with a L2 cache in the slot when running my old 604/150.

The Apple cache they used was P/N 820-0719-B. The engineer at ICNi told me he even swapped the old board out, and installed the replacement and it still refused to boot -- unless he put the cache in. The The replacement board (which i didn't see) was to be P/N 661-1783.

I'm taking my machine home tonite, and will try my old Techworks (for a 7200) cache. If it doesn't work, I'm gonna shoot it.

I really want to know what is with the TNT design, it's so infuriating.
Ted Anderson"

Andrew Salamone sent some tips that may be of help to 7500 owners with APS PowerTools:

" First of all, the 7200 graphics acceleration extension has got to go. As soon as I stumbled upon that, all my LDS-inspired (remember Spock in S.F.) video problems disappeared.

Also, the tech person (very kind and helpful, as well) at PowerLogix said that the motherboard cache should definitely be removed if possible. It's not possible. No matter what I tried, including removing the battery for 20 minutes, the computer could just not get itself together with out the cache. [many 7500 owners reported they needed a good cache installed to run reliably -Mike]

The PowerLogix tech person also told me that the newer, shipping version of the cache control panel can be a bit unstable. As Tad will tell you, it was extremely unstable in my case, immediately trashing any connected SCSI drive (and I do mean trashing) upon restart if the "enable on restart" box was checked. She sent me the older version, and presto, it worked the first time.

And importantly, don't wait until later to tell this to the unfortunate few who use APS PowerTools: get rid of it! Reinitialize all drives with something else (I used the Apple 8.1 (non HFS+)) BEFORE installing the card. It may save them countless heartbeats as they otherwise watch their drives be continually disemboweled by something in the PowerLogix arsenal (most likely, the control panel). You gave me this advice, and it was priceless. I wish that I had known this before my countless clean-installs and re-inits.

So, as I said, I am now running the card at 301 with the Ensoniq Paris card installed (for about 6 hours straight), and I have no symptoms whatsoever, except that my system acts like it's on crack, blazing through every task with unstoppable abandon. Thank you so much again for all your help and patience (especially Tad). Mac Gurus are the Bomb!
Andrew Salamone
CactusFire Productions"

And another report, amazing running at 341 Mhz!

"Hi Mike,
Your note today regarding the known incompatibility with Powerforce g3 cards and both the 7200 graphics accelerator extension and the catalyst based motherboards is something that has been discussed and solved on the messages board on your site (search for my name to read the messages). At least three people have had the same problem, including me (with my PowerCenter 150).

The solution is to turn off the 7200 graphics accelerator extension and leave in the motherboard cache. If the mother board cache is removed, the start-up hard drive gets munged and if the extension is enabled, you have to use virtual memory or there are serious video problems. I upgraded to an ATI Xclaim 3D and left in my cache and am happily running my PF 275 at 341/227 (MacBench 1206/1087 with LibMoto). Since I couldn't remove my motherboard cache without dire consequences, I installed NewerTech's MaxPower control panel and extension and used it to disable the cache. That yielded about a 5-7% speed improvement and did not introduce and problems. I did corrupt my hard drive 4 times before stumbling on the solution."

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