Quadra 605 Expansion Options

OK How far can you push a little 605? To a reasonable level, if you're willing to hunt around a little for parts. While the bigger-brother Quadras had multiple RAM slots, NuBus ports, internal CDROMs and the like, the 605 has to make do with pretty much just the one 72-pin simm slot and one LC-III compatible PDS slot. At first glance that's pretty limited - but there are more options. Firstly, as with most macs there's external SCSI, ADB and 2x serial ports, which accomodates CDROMs, scanners, modems and various ADB pieces. If you wanted to really stretch things, the 040 slot is another option - pop in a full 68040 and there's an FPU. Honestly however, that's not such a stretch, as Sonnet Presto PPC Q605 boards sit in that 68040 socket, adding a full 100Mhz of PPC 601, and leaving all regular internal expansion free. Ensuring you have 1Mb VRAM gives some pretty decent resolution/colour options, up to 256 colours at 1152x870, and 16-bit colour (Thousands) at 832x624.


Internal Expansion

These take either two 256k or two 512k 68-pin VRAM simms, 80ns or faster. A quick & simple upgrade to get 16bit colour at 832x624, or 256 greys on a 640x870 portrait display.

A 32Mb 72-pin simm on top of the 4Mb motherboard RAM gives 36Mb - and for many purposes this is more than enough, however some 64Mb and 128Mb SIMMS apparently work in 605s. LowendMac has more info on these.

68040 socket
Not technically an expansion port of a regular kind, but there are options here. Swap out the braindead 68LC040 for a full-FPU capable 68040 and you have yourself an FPU-enabled 605 capable of running Linux and BSDs. On top of this simple swap, there is another option - PPC 601 processor upgrades.

Note: The three cards below are practically the same product. Daystar produced a PowerCard 601-50/66 which ran at double motherboard bus speed (50 or 66Mhz) and a 100Mhz version. Apple's Macintosh Processor Upgrade was the Powercard601-50/66, and Sonnet later sold their version of the PowerCard 601/100 as their Sonnet Presto PPC 605

Daystar's PowerCard601 comes in two versions - one runs at double motherboard speed (50 or 66Mhz depending on the base speed), and the other runs at 100Mhz. This card installs in the 68040 socket, and Daystar warn in their PowerCard 601 installation manual "You will not be able to use the processor direct slot (PDS) after the PowerCard 601 is installed."

Apple's own Macintosh Processor Upgrade also fits in the 68040 socket, and provides a PPC 601 running at double the motherboard speed, resulting in a 50 or 66Mhz PowerPC. Apple however, warn that due to the space and power requirements of the Processor upgrade, that a LC PDS style card cannot be used along with the Macintosh Processor Upgrade.

Sonnet Technologies at one time produced a Presto PPC 605 expansion, a board which once again installed directly into the 68040 socket, giving a PPC601@ 100Mhz. While it's product manual does not specifically say that LC PDS cards would be unusable after installation, the sheer size of the PPC heatsink (and the warnings about not touching the heatsink) make it seem that it too would remove the ability to use any PDS cards.

While the manufacturers warn of power supply problems with a PDS Card installed (apart from the physical problems of fitting one) it appears there is always someone with a workaround. For an attempt at translating the contents of the japanese page, try the babelfish version.

If you have a Daystar PowerCard601(50/66) or the Macintosh Processor Upgrade and an overclocked Q605, Marc Schrier's Q605 speedup with PPC card page is well worth reading

First, read about the differences between a Q605's LC Compatible PDS and a real LC PDS. Now that's out of the way - there are a surprising number of devices made for an LC PDS. Unfortunately just about all of these are network cards, which limits the excitement :) - 10baseT, 10base2, AAUI, AUI - most options are covered. Due to the massive number of cards made, getting your 605 online is cheap-as.

Video cards are rarer, but some do exist. LowendMac has more details. I only have one LC PDS Video Card, and it's one of the better models, a Focus Enhancements LapisColor 2421. This is an accelerated 3mb card giving 24 bit colour in all resolutions up to 1152x870. I can't yet comment on the acceleration side of this one as I'm still hunting down the drivers. The big disadvantage to adding a 2nd video out on the 605 is a loss of easy ethernet access. A SCSI->ethernet adaptor should work here, however.

What can't you connect to a 605 with SCSI? That's about the only limit here. Pick any scsi peripheral that works on a 68k mac and it'll almost certainly be fine on a 605. Scanners, external hard disks, ZIP drives, ethernet adaptors, CD writers. A Quadra can handle 8x burning with few issues (burning direct from a fragmented HD will slow access, and may require a drop to a lower speed). The internal 50-pin SCSI connector and bay will take a 1/3 height drive. If you're worried about the maximum logical size drive macs can handle, read this LowEnd Mac article. In short - there's no inherent limit in mac hardware related to drive size, but there are a few related to the OS you're running.