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| "ultimate" 68k machine |
Posted by: kreats on 2008-03-22 01:51:51
trag: Yes, but:
"Supports the full range of NuBus master/slave transactions with single or block moves, including dumps and runs in which the main processor is master and the NuBus is slave , supports faster data transfer rates to and from the CPU bus, and supports NuBus 90 data transfers between cards at a clock rate of 20 MHz."
http://docs.info.apple.com/article.html?artnum=12738&coll=ap
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Posted by: trag on 2008-03-24 09:01:49
I'm sorry, I seem to be missing your specific point. The support for block moves is nice, assuming that was not available before, but transactions to and from the CPU are still at 10MHz in all Macintosh machines. Only card to card transactions have the option of running at 20 MHz.
If you doubt this, look up the specific Apple Hardware Developer Note for each NuBus machine after the Q900 and you'll find that they all stick to 10 MHz transactions with the CPU.
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Posted by: MacSE/30 on 2008-03-24 09:14:11
Is it possible to downgrade the Q950 oscillator to 50 MHz and use QuadDoubler 50 MHz upgrade?
Just a thought!
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Posted by: kreats on 2008-03-24 20:21:17
Well the point is that the q840av notes say it is doing something faster wrt nubus speeds through the cpu. I assume they are comparing it to existing quadra models (such as the q950).
Assuming Apple isn't flat out lying, what is responsible for this increase in speed and did anything take advantage of it?
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Posted by: Microns on 2008-03-30 14:53:04
Personal preference:
840av (one that will overclock to 48Mhz, Nubus 90 standard, two Apple Hi-Res color monitors, max out the VRAM and RAM)
Add:
FWB Hammer SCSI-2 card (more compatible with the overclock than the ATTO cards)
FWB External Ultra SCSI array
Radius Thunder IV 1600x1200 with 4 DSP daughter board
Radius Photoengine coprocessor card
Wacom ADB tablet
Then crank up Photoshop and watch the 8 coprocessors blink away...
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Posted by: Temetka on 2008-03-31 02:22:50
I counted 6 cards in your config. Will the 840AV hold that many?
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Posted by: Quadraman on 2008-03-31 04:05:42
No, an 840 does not have that many slots. A 950 doesn't even have that many slots.
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Posted by: kreats on 2008-03-31 04:57:01
that's only three cards there - the scsi array and wacom tablet are not nubus cards.
If you were running out of slots, you could get an external nubus enclosure, but I'm not sure how well this is supported (Only avid setups?).
btw - the photoengine works cooperatively with the thunder IV?
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Posted by: Temetka on 2008-03-31 05:37:23
Aaw crap!
I made a mistake. A newbish one at that. Yes you are only using 3 cards. I went back and re-read your post and attempted some form of reading comprehension. Thinking about the setup made me almost slap my forehead. Almost.
Sorry about that.
8 Co-Processors you say?
Anything else besides Photoshop take advantage of all those spare cycles laying around?
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Posted by: Microns on 2008-03-31 06:01:28
kreats is correct, only three nubus slots used in this config.
The Radius and Adobe software allow work to be spread across all eight DSP chips (4 on the Thunder and 4 on the Photoengine) in this setup. The simplest and most direct way to see this is to run with the case off the 840av and look for the LEDs (1 per processor; upper right hand corner of the boards). If they're on (flashing on/off) the processor is active.
The Radius DSP hardware accelerators were developed specifically for Adobe software and use the "Adobe-Charged" system. I know them mostly from Photoshop (versions later than 2.5.1 supported) but don't recall if they also work with Adobe Premiere.
Cheers...
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Posted by: kreats on 2008-03-31 08:41:51
which makes me wonder how far does it scale? Say a q950 plus a thunder IV and 4 photoengines?
You'd hope your gaussian blur would be plenty fast by then!
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Posted by: Unknown_K on 2008-03-31 15:28:08
You are limited by the Nubus controller on how much data you can fling around between the cards. 4 DSP chips seem to be plenty anyway.
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Posted by: Quadraman on 2008-03-31 18:16:17
What is the point of loading up an old Mac with DSP's these days? Radius Rockets aren't that cheap and newer Macs can do anything faster.
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Posted by: igor_av on 2008-03-31 18:32:57
The same as collecting old 68k mac... Don't you think? 😉
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Posted by: Quadraman on 2008-03-31 18:36:25
What I mean is, I know they are cool to have, but if you are actually going to use them, isn't using a faster machine and newer software more productive? And if you use them, you run the risk they will stop working so you spend a huge amount of money on a collectible peripheral and then wear it out.
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Posted by: Microns on 2008-03-31 20:25:53
kreats - In my hands the Photoengine cards appear to scale very nicely. I have never timed things but the Photoshop speedup seems roughly proportional to the number of Photoengines. One thunder IV plus two Photoengine cards makes 12 DSP coprocessors and the speedup is quite noticeable.
Unknown_K - Nubus speed does not appear to be limiting but, as I said, I have not timed things.
Quadraman - Just speaking for myself - the point is that there is no point. There are many better ways to run Photoshop. BTW - The Radius Rocket is not a DSP-based coprocessor and what are we wearing out? The ROMs will eventually degrade but that will happen with use of not.
Cheers...
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Posted by: Unknown_K on 2008-03-31 21:12:09
Old software with old hardware can be very productive as long as you do not need some newer feature to do your work ( and don't need to use the internet).
I have scanned in some large pictures and cropped them in photoshop 3 on my Q950 and it wasn't realy slow. Saving as JPG took a little more time then it would have on my main machines, but the SCSI scanner wasn't running slower and I had plenty of RAM to work with.
Most people do not use most of the features of newer apps anyway.
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Posted by: Quadraman on 2008-04-01 06:28:51
The Radius Rocket is not a DSP-based coprocessor and what are we wearing out? The ROMs will eventually degrade but that will happen with use of not. Yeah, I remembered that after I entered the reply but was too lazy to fix it. I should have used 'accelerators' as a generic term.
And circuits wear out faster when you have voltage running through them than when you have them packed away.
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Posted by: Charlieman on 2008-04-02 13:27:02
Hmm, that's interesting. No listing for the 2300, and none for the beige G3. From memory, the latter is a mere 5MB/s.
In fact no listing for any of the PPC Powerbooks. SCSI on the beige G3 was deliberately designed as a low end interface to support legacy scanners, Zip drives etc. Apple had lost interest in creating their own high performance SCSI solutions, hence the market for Adaptec SCSI cards.
For the PowerBooks, assume slow SCSI. Were there any good PCMCIA or PC card SCSI adapters?
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Posted by: kreats on 2008-04-03 14:53:16
The adaptec powerdomain PCMCIA SCSI card (mac variant of slimscsi) is probably what you want here.
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