68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
My First Quadra
Posted by: jeremywork on 2020-05-03 18:25:14 This may be a few years old, but did you get every info needed ? I got access to a few Q650 & Q800s Reading through, it looks like we have one confirmation of a Q800 with 60ns soldered RAM, and one confirmation of a C650 with 80ns soldered RAM. No 650s designated Quadra (33MHz CPU) were shown yet. The main question left is: • Do all 33MHz "Quadra" badged models contain 60ns memory? -or- • Do all 650 models contain 80ns memory, regardless of CPU speed? One other note: I've read elsewhere in the forum, the switch that controls the gestalt ID also affects the machine's ability to be overclocked. 25MHz boards are only stable to about 35MHz, but if set to 'Q800 mode' they will be stable past 40MHz.
Posted by: jeremywork on 2020-05-03 19:03:43 One other tidbit: according to Apple's Memory Guide, all Centris variants of the 650 had only 4MB soldered memory, while the Quadra 650 variants had 8MB, like the Quadra 800. While it does specify 60ns memory for the 800, it only makes one single 80ns designation for the 650s. Very curious to see what speed is on the Quadra 650 boards... http://akarchive.digidesign.com/support/docs/memguide.pdf (PDF Pg 28) Also off-topic, the 650 page explicitly states that 1, 2, and 64MB SIMMs are not supported. The 800 page has no matching note, and we also know that both models can be modified to use up to 128MB SIMMs. http://www.synack.net/~bbraun/djmemcrom.html
Posted by: jeremywork on 2020-07-25 13:06:01 This Quadra 650 on eBay has a closeup showing 80ns onboard RAM. As long as that's the original board, I'd say that's the answer: only the Quadra 800s have the fast RAM, despite being otherwise identical to the Quadra 650. https://www.ebay.com/itm/Working-Apple-Macintosh-Quadra-650-w-power-supply-24MB-Memory-no-hard-drive/324240944843
< 9