"ultimate" 68k machine

[Maconthemove]

Another possibility is the Daystar Quad 040 running at 40 MHz with a 128k SRAM cache, It fits into the PDS slot.

 

[Unknown_K]

You might be able to overclock that.

 

[p.amadeus]

Probably could overclock it. But let's not get ahead of ourselves, I still need a Quadra to start with before I even begin to consider upgrade paths! 8-o

 

[Unknown_K]

There is a 950 on ebay currently

 

[Maconthemove]

How would you speed it up. Change a part on the motherboard? Could the same mod be done to a Q650?

 

[Temetka]

I'd be interested in seeing some benchmarks from a 950 with an over clocked '040 in the PDS slot.

There are no CPU upgrades for the 840AV are there? I know PPC is not gonna happen, but could I theoretically stick a 50MHz '040 in it, swap oscillators and be on my way?

 

[Maconthemove]

FYI

Quadra 950

The Quadra 950 has a 67 MHz oscillator which runs the processor at 33 MHz. The max oscillator you can replace it with is 92.9405 MHz, to run the processor at 46.47025 MHz. With an Apple PPC card installed, the max oscillator you can use is 80 MHz, which will run the 68040 at 40 MHz and the PPC card at 80 MHz.

Info from http://homepage.mac.com/schrier/spec.html

 

[p.amadeus]

But isn't this is only in terms of clock chipping, it is still possible to install an upgrade card with an 040 @ 50mhz actual speed, correct?

 

[SiliconValleyPirate]

I still don't get how people consider the 950 'superior' to the 840av. The 950 was built off an older architecture, which included slower, non interleaved RAM and no onboard video, and, although it was able to hold more NuBus cards, had a full PDS slot and was able to take large number of disks, it still wouldn't outperform an 840av in real terms even with the 50MHz card.

I fall on the side of the 840av because it was revolutionary in the way it pushed the limits of what you could do on a 68k, with DSP integration, Video capture hardware onboard, and CD quality 48kHz DSP accelerated audio. It also had a faster stock CPU, and uses 72-pin 60ns Interleaved RAM which makes the RAM bus significantly faster. The only drawback is the case. It's nasty. I'll openly admit that. I've long since given up using the internal disc bays and use an external Sun MultiPack array hung off the Jackhammer's 68-pin SCSI port instead.

I suppose which one wins out depends on what you are looking for, but technologically and innovationally the 840av was, IMHO, the ultimate 68k.

As a side note, I always look to Dave Haynie's notes on the Amiga 3000+ with a tinge of sadness, and think the 840av architecture is really everything that the Amiga 4000 should have been.

 

[vassilizaitsev]

I think I've just evened up the poll [] ]'>

An 840av for me... why, cos upgrading the ram is fairly simple & it does great things without me having to mess too much with it.... I don't have a soldering iron where my hand should be?

It depends what you want to do with the machine, but read up on the good points of the 840av, interleaved ram, faster nubus slots..... Check out cinemafia's old posts, he had some good nubus/scsi bits in his 840av.

Ultimate.... you mean best stats... fastest machine?

Try a Milan, or Hades (Atari ST clones) or an overclocked Falcon, look for the French guy who wrote aniplay, he has a pretty fast 68k machine.

For Macs, the 840av has the "cult" status, because of of powerfull it is out of the box.

 

[kreats]

no onboard video? bzzt... q950 has very fast onboard video

Out of the box doesn't come into it - we're talking ultimate here. With the 50MHz upgrade I'd bet they would bench at least equally as fast in every respect, but the 950 is more expandable.

Feature for feature, a tweaked 950 creams a tweaked q840av (I think there was a newer upgrade for the 840av - but try finding it). Even the Q800 beats the 840av as it at least had a PDS slot (and could possibly take the 950 upgrades as it operated at the same clock frequency).

Most of the differentiators named above were either never used or were inferior solutions anyway. e.g.

You want DSP? Thunder IV

AV inputs? Get a spigot AV or videovision or an avid setup (for which the 950 was the supported model)

You want high quality audio? Audiomedia II

Faster SCSI - atto IV or jackhammer

Want 72 pin ram (and a PPC)? Powerpro 80MHz w/ ram expansion

And most importantly you don't have to choose which cards to leave out - you can have it all!

Plus you keep AUX compatibility.

The only thing bad I'd say about the q950 is the noise - which can surely be fixed.

PS: I would like to see some benchmarks - maybe macbench your 840av's & let us know?

 

[Bunsen]

If you go to everymac.com, select upgrades, then list by compatible machine, you'll find there are indeed a couple for the 840AV

 

[p.amadeus]

that's funny I don't see any....for the 660AV yes but not the 840AV

http://www.everymac.com/upgrade_cards/by_system/index.html

 

[Bunsen]

OK, that's strange. I could have sworn I was looking at one there the other day.

Going back to their upgrades by manufacturer listing, it becomes clear that they don't have details for every upgrade ever.

 

[p.amadeus]

There is no doubt about that

 

[Temetka]

Hmm, there is a 50MHz '040 for the 660AV.

I would rather have a 660AV than an 840AV anyways.

Reasoning is that I love the form factor and it is plenty of 68K Mac for me. I just tinker with the 68K's as they pre-date my switch.

I wonder why there are no PPC's upgrades for the AV series though. Does it have something to do with the DSP's?

 

[Unknown_K]

The 840av and 660av have no PDS slot for upgrades. I also think the AV section and DSP are probably tied to the CPU clock so messing with that will probably cause problems.

 

[Bunsen]

Any reason why you couldn't use a CPU socket upgrade for a Centris 650 in a 660? They both run a 25MHz native CPU

 

[igor_av]

The 840av and 660av have no PDS slot for upgrades. I also think the AV section and DSP are probably tied to the CPU clock so messing with that will probably cause problems.

I think we discussed that in another thread. At that time, we agreed that the PDS slot in the Q660av was not a real PDS slot...

Meanwhile, I've checked the Quadra 660av and 840av Developer Note and found the following information on page 46 :

The Macintosh Centris 660AV (but not the Macintosh Quadra 840AV) can accept an accessory card that plugs directly into the main circuit board instead of into the adapter card shown in Figure 2-13. An accessory card plugged into the main circuit board can gain access to the processor as well as to the DAV bus. The resulting processor-direct slot (PDS) capability is similar to that of the Macintosh Centris 610 computer, described in the Macintosh Centris 610 Developer Note.
The Macintosh Centris 610 computer uses an AMP type 650231-5 connector for PDS cards; the Macintosh Centris 660AV uses an AMP type 650231-3 connector. Because the corresponding pins are aligned, it is possible to design PDS cards that work on both models.

So, yes, the PDS slot in the 660av is a full-fledged 040 PDS.

 

[igor_av]

Any reason why you couldn't use a CPU socket upgrade for a Centris 650 in a 660? They both run a 25MHz native CPU

CPU sockets are compatible (not the PDS though) BUT the upgrades won't necessarily physically fit in the case. I once tried to install a Quadra 650 Quaddoubler in a Quadra 660av. Didn't work because it was overlapping the CD drive tray.