Quadras: 650 vs 630 vs 800 vs 950

[Bunsen]

As I've just ordered a couple of QuadDoubler /edit/ NewerTech Quadra Overdrive / accelerators (/edit/ one 33MHz 650 compatible Overdrive Plus with 128kB cache and one cacheless 25MHz 605 version, both runnning 50MHz full '040s/), I'm casting about for the bestest possible Quadra motherboard to mount them in.

Here are various assorted and somewhat rambling thoughts to that end.

Looking at the specs on LEM, it seems the 650 and the 800 are identical. Same CPU, same benchmarks, exact same paragraph about Q950-beating interleaved RAM and faster SCSI.

And given that the one is a drop-in replacement for the other, and this:

it really detected a Q650 mobo although it was a Q800 one.

... are they in fact the exact same motherboard?

Is 10% speedup worth giving up the extra 2 Nubus slots and twin SCSI buses in a 950

Is there any way of creating a SCSI RAID on a 68k machine?

And if I was willing to trade in Nubus slots for IDE, how would either of these compare with a 630, which also sports a 33MHz CPU?

I'm leaving aside space issues here, as it's likely the final monster will end up in a custom case of some kind. I'm also not averse to a bit of soldering and adapter fabrication to solve any connector clearance issues.

The 630 'board has the advantage of possibly fitting into a SE/classic shell. It and the 650 also share the substantial advantage of being in my possession, and not requiring purchase and trans-Atlantic shipping at great expense.

Another consideration - 630 DOS CPU card, with the QuadDoubler on top of that ...

Finally, compatibility with some form of Unix would be a plus.

à vous, mes amis

 

[beachycove]

Is there any way of creating a SCSI RAID on a 68k machine?

Yes. You can create a nice little RAID (various sorts) with a JackHammer card, a couple of 68 pin scsi drives, and an installation of the appropriate version of FWB Hard Disk Toolkit. You can no doubt create a RAID with 50 pin drives and the FWB software also. So a Q950 has its advantages.

 

[kreats]

where did you get the quaddoublers from?

If it's designed to double a 33MHz (I assume to 50MHz - not 66MHz), why not just use it in a Q950?

If you're talking the newer tech. ones, they are probably system specific - each has it's own model number at least (I think the q900 and q700 have the same model number tho). btw gotta watch out for the centris versions of these as the c650 was only 25mhz.

Don't suppose you could do some pics anyway?

EDIT: actually I don't think there was ever a 33MHz version of the quaddoubler, so I'm pretty sure you're talking about the newer quadra overdrive ones.

 

[Unknown_K]

The one I have for the 950 is 50Mhz so thats 1.5x the 33Mhz bus. There were versions for the 900 that are 2x25Mhz bus.

 

[tmtomh]

Looking at the specs on LEM, it seems the 650 and the 800 are identical. Same CPU, same benchmarks, exact same paragraph about Q950-beating interleaved RAM and faster SCSI.
And given that the one is a drop-in replacement for the other, and this:

it really detected a Q650 mobo although it was a Q800 one.

... are they in fact the exact same motherboard?

Yes, basically. The only noticeable, and non-user-upgradable, difference is that a Q800 will always have 8MB of soldered mobo RAM, while a Q650 mobo may have either 4MB or 8MB soldered on. The only other thing is that if you're buying a board that hasn't been upgraded (or stripped), the Q800 board is more likely to have 1MB VRAM installed, while the 650 will have 512k.

Is 10% speedup worth giving up the extra 2 Nubus slots and twin SCSI buses in a 950

I would say, absolutely yes. I've never had a need for more than 3 NuBus slots, and I've never found any need for more SCSI peripherals than a single bus will accommodate. And while it may be heresy to say so here, I've never felt particularly warm and fuzzy about the gigantic, incredibly heavy Q900/950 form factor. I had an AWS95 (Q950 with extra PDS card) once, and while it was fun, I sold it because it was so darned big and I couldn't get it to boot from the fast SCSI PDS card.

And if I was willing to trade in Nubus slots for IDE, how would either of these compare with a 630, which also sports a 33MHz CPU?

You know, that's a really good question. The PPC Macs based on the 630 architecture were terrible, but the '040-based 630 platform itself is really nice. The ability to use IDE drives is very nice - BUT, you're limited to 4MB of mobo RAM and only one SIMM socket. Some models have two SIMM sockets (LEM says the Performa 631 does), but these came with 'LC040 CPUs. So you'd have to go get a full '040 CPU, and even then you might or might not be able to use SIMMs larger than 32MB. So a Q650 or 800 will easily allow you to install more than 68MB RAM without spending a lot of money or 64MB or 128MB SIMMs, and without having to spend any money on a CPU upgrade.

Another consideration - 630 DOS CPU card, with the QuadDoubler on top of that ...

I don't know if both cards will work stacked like that, but I can say that I had a Performa 640CD/DOS once, and it was the most fun I've had using Windows on a 68k or PPC Mac - very cool!

Finally, compatibility with some form of Unix would be a plus.

Others may have a different view, but my opinion is, if you really want to use *nix on this machine, go with the 650/800 board. The IDE-based Macs like the 630 are an absolute nightmare for *nix IMHO. I've never successfully installed it on any of them. And the 650/800 have the extra bonus of being supported by A/UX.

Best,

Matt

 

[Bunsen]

where did you get the quaddoublers from?

dlchief58 on ebay - he has more.

why not just use it in a Q950?

Because I don't have one, and I'd have to import a motherboard from the US - which costs a bomb - and find a case for it. Importing a whole Q950 is out of the question. And the 800/650 are supposed to be slightly faster.

Also, ADB doesn't work on the 950 in NetBSD apparently.

I'm pretty sure you're talking about the newer quadra overdrive ones.

Quite right, my mistake. Cache too [] ]'>

 

[Bunsen]

Thanks for the comments tmtomh. They showed up while I was typing the above entry.

AWS95 (Q950 with extra PDS card) / I couldn't get it to boot from the fast SCSI PDS card.

LEM implies that it'll only boot "Apple's version of Unix" with the card installed

So you'd have to go get a full '040 CPU

The Overdrive has a full '040 onboard

a Q650 or 800 will easily allow you to install more than 68MB RAM

Good point

without having to spend any money on a CPU upgrade.

Already spent

I can say that I had a Performa 640CD/DOS once, and it was the most fun I've had using Windows on a 68k or PPC Mac - very cool!

Inspiring, thanks. Just a thought, but is there anything to prevent me using the 640 DOS card in another (33MHz '040) machine?

The IDE-based Macs like the 630 are an absolute nightmare for *nix IMHO. / And the 650/800 have the extra bonus of being supported by A/UX.

Well then, I think we have a weiner [] ]'>
Pity it won't fit in an SE/30 shell, but that's why I ordered a spare Overdrive }

Another point: seems from a quick search of the NetBSD forums that you need to disable cache on the Overdrives to boot. The second one I ordered was cacheless for this reason (and price). It's also the version for a 605 (25MHz -> 50MHz).

I also ordered some of his variable speed overclocking kits. Let's see ... peltiers or liquid cooling....?

 

[tmtomh]

AWS95 / I couldn't get it to boot from the fast SCSI PDS card.

LEM implies that it'll only boot "Apple's version of Unix" with the card installed

True - but I couldn't get it it boot that way even with A/UX.

The Overdrive has a full '040 onboard

Yes, well, I'm an idiot - of course I forgot about that - my bad! [:I] ]'>

is there anything to prevent me using the 640 DOS card in another (33MHz '040) machine?

AFAIK it will work fine in any other 630-based machine. But I'm not sure if it will work in other '040 machines.

Good luck - let us know how it turns out!

M

 

[TylerEss]

Peltier + liquid cooling is the win; remember that when you're peltier cooling you need to shed not only the heat from the CPU but also 50+ W of heat from the junction itself; watercooling helps greatly in that capacity.

 

[Bunsen]

640 DOS card in another machine?

I'm not sure if it will work in other '040 machines.

A quick bit of Googling turns up this over at the 'fritter:

Theoretically the card from a Performa 640 Dos compatible *could* work on an LC 575, as the 640 Dos Compatible card plugs directly into the 68040 processor socket/

BUT--, thing is, this card does not have a connector for external video out / as it does all the video output via a special connector that, well, piggybacks with the internal circuits of the Performa 640.

So, barring close examination of that internal connection and what it plugs into, that sounds like a pretty definite no.

Still, I'll have a PDS slot free for a Houdini card

(/edit/ / and one cacheless 25MHz 605 version, both runnning 50MHz full '040s/)

Hm. 50MHz CC Mystic, anyone?

 

[Temetka]

A 50MHz CC does indeed sound like fun.

However what purpose would it serve? What tasks would you be using the CC and it's tiny crappy (now, not then) screen for?

I have an SEFD and I hardly ever use it. It's just too slow, has a bad screen (my opinion, the screen functions great and is bright) and so on. I fire it up to feel nostalgic. Spending money on that machine for my needs would be pointless.

Your needs may vary. As I type this the thought of a 50MHz CC does make me feel warm and fuzzy though. If only you do video out and hook up a real screen, then it would be tres cool.

 

[trag]

A few thoughts/experiences...

Reports are that the Q630 will take 128 MB SIMMs. So the capacity would be at least 132 MB. The ones with two slots, again reportedly, cannot use a double-banked SIMM in the second slot, so its limit would be 64 MB for a total of 196 MB. I have not tried this myself.

The video performance on the Q630 is very nice, but I think the VRAM capacity may leave something to be desired.

The edge connector on the motherboard of the Q630 makes it an unlikely candidate for installing in an SE/30, unless you want to adapt all your connections to that edge connector.

The Q63x and related Performas and LCs can be taken to 40 MHz with a simple resistor moving hack. As for all such hacks, see Marc Schrier's Clock Chipping Home page for details.

While it is possible to do SCSI RAID on 68040 machines, I think you'll find the results disappointing and actually slower than getting a single hard drive with performance that can saturate your interface. Kaye (of MacGurus) has done many RAID tests on PPC NuBus hardware with dual JackHammers and very fast SCSI drives and found that the performance was not substantially better than single drives. A single fast drive can so saturate the NuBus, that there is no advantage in running two drives at a time.

Now, if all you have is older slower SCSI drives, then a RAID could add some performance. For example. while the interface on an ST32550N (very early 2 GB Barracuda) is rated for 10 MB/s (Fast SCSI II) the drive itself can only deliver about 6 MB/s of performance. Similarly, the ST32550W (Wide version) is rated for 20 MB/s interface performance, but again, only delivers about 6 MB/s of performance. They have the same disk mechanism, and that's the best the platters and heads can deliver at 7200 RPM.

Combined in a RAID 0 on a single Jackhammer in a Power Computing Power 120 (120 MHz 8100 clone) two ST32550W drives give about 8 MB/s of performance. In other words, nowhere near double what a single drive delivers.

If one adds a third drive to the JackHammer and the RAID, performance does not improve in any measureable way.

However, if one then puts an ST32550N on the built-in Fast SCSI bus, and adds it to the RAID, the performance is boosted to 10 MB/s. Adding a second drive to the FAST SCSI bus does not improve performance. Finally, adding a fourth drive, another ST32550N to the built-in unenhanced (5 MB/s) SCSI bus and adding this fourth drive to the RAID brings total performance to 12 MB/s.

Pretty pathetic (and noisy and hot, the early Barracudas were *NOISY* and *HOT*) performance for the amount of effort input.

It is possible that Quadra results might be different, since the NuBus interface to the host machine is a bit different, but I doubt it.

If one buys a newer SCSI drive, which will also be quieter and cooler running, which delivers performance in the neighborhood of 20 - 30 MB/s and puts it on the JackHammer, one will almost certainly see much better performance than can be achieved with a RAID of older slower drives. And adding more new drives to the RAID won't really improve performance because one fast drive bottlenecks the NuBus.

 

[Bunsen]

saturate your interface

Ooh baby. Talk nerdy to me