PM 8600 reports wrong size RAM?

[jrwil]

You're right, I think that narrows it down to the MB or the ROM. The DIMM chips work. 

Quite a PCI roster there. One other reason I installed 8.6 was to see if the Radeon 7000 64mb I have would finally produce an image — no dice. I don't think my model plays well with Classic. What model 7000 do you have?

 

[jeremywork]

I just came across this unrelated but similar quote here regarding memory in the beige G3:

http://lowendmac.com/1997/beige-power-mac-g3-1997/

"The Beige G3 supports 256 MB DIMMs, but they must be built using 128 Mb chips. DIMMs built with 256 Mb chips will work, but the memory controller will only see the first 128 Mb of each chip. Compatible 256 MB DIMMs will have 16 memory chips, 8 on each side."

The Radeon 7000 I purchased is still for sale on eBay here: https://www.ebay.com/itm/263487427195

It only has official drivers for OS 8+ but can actually be run accelerated in 7.6.1 thanks to some prior knowledge here: http://main.system7today.com/articles/videocards.html

(Click through to the help center where you can download the System 7 driver package)

It even properly runs the Aluminum DVI 23" Cinema at full 1920x1200 resolution in both 7.6.1 and 8.6! I was quite surprised as this display is known to be particularly hard to satisfy even by newer machines like G4 towers.

EDIT: even without drivers, the 7000 should display UNaccelerated video in both 7.6.1 and 8.6... does your card work in other Macs? Perhaps it's a PC BIOS or it wants to be in a different PCI slot?

 

[jrwil]

Man, here's hoping System 7 Today is never taken down. Good to hear of someone who's used those drivers successfully in System 7. My 7000 is very similar, but has S-Video instead of composite and a different label on the heat sink. I've tried it in a 6500 and the 8600 with the same result. I suspect it's actually a PC variant, despite what the eBay listing said!

 

[jeremywork]

As I was re-reading the eBay listing, I noticed it specifies a firmware that allows a boot screen on older PCI powermacs. If I recall correctly ATI cards can only be flashed in a PC, but I could try to dump the ROM. Not sure how it would play if the card happened to have any differences in the hardware though...

The composite port on mine is actually soldered to a larger S-video header on the board (I used to have an S-Video version in a Quicksilver G4 I sold.) I imagine with a steady soldering iron it would work perfectly with an S-Video output.

 

[jrwil]

Just Googling around, it looks like it was possible to flash the ROM on a Mac, but the historical repositories for those ROMs (and some instructions) are mostly dead. I do have a Rage 128 that's working fine for now, and is probably more than adequate for my needs. It would be great to double the RAM of that card. It all comes back to RAM? LOL. The Rage 128 pushes 1600x1200 just fine on a 20" Dell Ultrasharp (albeit VGA), although I haven't tried much gaming at that size. If yours is working well, I wouldn't touch it. I gather these flashing procedures are pretty finicky.

 

[trag]

The tidbit about the buffer chip on the memory is an oldie but a goodie.  I apologize for not remembering it in our earlier discussion.     Interesting old discussion here:  http://duc.avid.com/archive/index.php/t-18582.html

Also, the R7000 most certainly will work in System 7.6 with or without drivers.   It does sound like your card is a PC card without proper Mac firmware installed.   The PC versions of the cards have a Flash chip with 1/2 the capacity of the Mac version.   To convert to Mac version, one must either use an edited version of the Mac firmware (has issues during start up splash screen and such) or replace the 8 pin flash chip.   Replacing the flash chip is really pretty easy.   AS mentioned, there are only 8 pins, and it's over by itself near the top front of the card.    

One version of the ATI updaters will flash a blank chip in a Macintosh with the Mac firmware and you can update to the last, latest version from the there.  The "special" version ended in 2.08, IIRC.   I converted about 100 of these back in the early 2000s.   I always replaced the chip.   Others flashed the modified ROM onto the smaller flash chip, but this has a  couple of problems.   It has the issues mentioned above about display during the boot process, and it also means that updates either can't be done, or updates require the same amount of work as the original flashing of the card.   Now days, with no new updates, it doesn't matter as much.  Back then, it made a difference.

 

[jeremywork]

Update: 2 of the 3 OWC 128MB modules were the correct buffer for my system, and I can confirm they read properly as 128MB modules, not 64MB (so the board was not at fault in this case it seems)

 

[jrwil]

Interesting. Did you buy those from OWC, or secondhand somewhere?

 

[jeremywork]

Unfortunately they were secondhand on eBay... Had OWC not discontinued them I'd feel confident buying new from them.

 

[trag]

That is interesting @trag, because I was wondering why ASP reports the Model name as "Power Macintosh 8500 series." The ROM revision is $77D.34F5.

Hmmm, well there's enough info there for ASP to report it as an 8600.   Unless ASP just never reports 8600 and always says 8500.

The chip set other than the ROM is identical between the 8500 and the 8600.  They changed the power supply connector a little and there's a slight difference in the voltage supply lines of the CPU socket on the 8600 Enhanced.   But other than that, the boards and chips are identical.   They got a lot of mileage out of that chipset design.   It was a pretty good one, except for a stinkin' PCI bug wrt PCI-PCI bridges.  Can't believe they didn't get that right, but maybe they thought it would never come up.