I have a Dual 1GHz MDD PowerMac G4. Packed it out with 2GB RAM and some 500GB disks.

I still have the original 400W power supply in mine. There was an offer, which I qualified for, to replace the 400W supply with a 350W and replace the fans in an effort to reduce noise. By then I was used to the noise, and it's a lot better in OSX than in OS9. I don't think the replacement fan and supply made that big a difference according to posts on Apple Discussions at the time for some people anyway.

Make sure you get a dual CPU version, if you go to Tiger or Leopard it helps immensely with all the background tasks that run.
The MDDs all offer large drive support on the internal IDE buses, supporting drives over 128GB. I have 3x500GB and a 120GB for OS9 booting. I also have another 500GB and a 1TB attached by FireWire.
The MDDs still get a good price on eBay - about £100 - £140. For some reason, so does your iMac G4, about £80-£120, even more with all original disks, keyboard mouse and speakers. I had one of these too, 800MHz, good for its time. Bought it just after I bought the MDD, it aged pretty quickly, the MDD stayed usable until a month ago when I switched to my PMG5 (MDD still used for server tasks).

The QuickSilver G4 (2002) model also has large drive support (OSX 10.2 or later required) - I have one of these as well.
Again, if you go for a QS 2002, make sure it's dual processor. up to dual 1GHz also.
It only has 3 DIMM slots, maxing out at 1.5GB.
It only has 1 optical drive bay (and a Zip drive bay).
It only has one internal IDE bus for drives, supporting 2 drives.
It has space (and cradles) for more drives, but you'll need an IDE or SATA card to use them.
It is more limited in the video cards it can support - mine came with a Radeon 7500 32MB. The MDD came with a Radeon 9000 Pro 64MB.
But the QS 2002 models can be cheaper on eBay - £60-£80.
And they are (relatively) deadly quiet.
But they use PC133 RAM, which is expensive compared to the DDR RAM used in MDDs - only an issue if had to hunt down more RAM maybe discarding RAM already installed.

If you lived in Edinburgh, you could take one (or both) of my old 17" Apple Studio Displays (CRT with ADC connector) away. In original box, etc, etc. They're capable of higher resolutions than my day-to-day 17" Apple LCD Studio Display (tops out at 1280x1024).

For under £40 you could look at a dual Digital Audio G4 - I have one of these too, a dual 533MHz.
Again, only 3 RAM slots, 1.5GB max
No large drive support, unless you buy an IDE / SATA card.
One optical drive and one zip drive,
Deadly quiet.
But even more limited on video options.

Simple questions,
how much do you want to spend ? More than £150 you could start looking at a G5, iMac and PowerMac.
do you need OS 9 booting ?
which spec of iMac are you looking to move away from ?

Perhaps the topic should be "How loud are Power Mac MDD G4s really?

bertyboy really sums it up. Just to add my tuppence worth: Avoid the MDD's if possible and go for the 1GHz QuickSilver 2002 duals if you can locate one for sale. This model is excellent and quiet in comparison to the MDD "wind tunnels". Also the earlier dual Digital Audio G4 533MHz is a good choice, slower than the QS 2002s obviously, but a rock solid work horse. I also own both the QS 2002 and the DA G4s, they've never missed a beat. These days I tend to use the DA for Mac OS 9 apps only.

From my little spot on this planet, you can pick up QS 2002's for approx. AUS$100 and the DA's for half that or less. CRTs if any, usually get tossed in for free just to get rid of them, otherwise, a display will generally cost extra.

The same iMac I had.

Options-
The dual procesor DA G4's - the lack of large hard drive support may put you off, and they're not going to be that much faster than your iMac. The dual processor model (533MHz) was ONLY available as a custom buld by Apple - so they're very rare. Video cards are on a par with what you have already.

The dual 1GHz QuickSilver 2002 - Fast, quiet, large drive support (with OSX 10.2 or later - more on this at the end). Max of 1.5Gb RAM, but this is the mac OS9 can use anyway. Good video - came with a GeForce4 MX 64MB or a GeForce4 Titanium 64MB as custom build to order. The video supports ADC or VGA.

A dual processor MDD - Faster still (faster RAM and bus), large drive support, max of 2GB (only 1.5GB can be used in OS9), and even better video options, came with Radeon 9000 Pro 64MB, but can take Radeon 9200, Radeon 9600 or Radeon 9800. 9000 Pro supported ADC and DVI, all the others are just DVI x2 (I THINK). Thee cards are expensive when they come up, so it would be good if they were already installed in the MDD. Can't guarantee that they'll all work in OS9 either. No worries though, the Radeon 9000 Pro is fast enough for any sofware OS9 has to offer.

Important Notes-
All QS 2002 models can boot OS9 natively, but like the MDD, they need a specific version of OS9.2.2 as a minimum. I used the MDD OS9 on mine. Works perfectly, and we can set you up with it if needed.
OS9 can only address 1.5GB of RAM - still more than you'll ever need in OS9.
OS9 has a disk volume limit of about 192GB. I've found OS9 can use larger volumes (my multiple 500GB drives) but it can only boot from a "volume" no larger than 192GB (a 200GB disk formats to 186GB). This is a "volume" limit, you can still use larger drives, but you'll need to partition the disk which will boot OS9, into a partition no larger than 192GB and whatever else.
Large hard drive support is only offered if you format the drives in OSX 10.2 or later.
The Dual 533MHz is the ONLY DA with dual processors. The other models only ever came with a single G4.
There is a 2001 QuickSilver range of Macs, they do NOT have large drive support. There is a dual 800MHz model in this range. Fast, quiet, but limited to 128GB drives on the internal IDE bus.
Now the good notes-
There is a Hardware System Pref available in the Developer (XCode) Tools that allows you to "nap" the MDD processors when they're not in use. This brings the temperature way down, from a constant 59C to about 34C when the Mac is idle. Makes a big big difference to the fans too. So the MDD is relatively quient when it's not CPU intensive. Of course, it's only available for OS X. We can help you with this too.
The large hard drive support is all irrelevant if you install an IDE or SATA expansion card. These can cost a lot, over £60 but if your Mac (QS2001 or G4 DA) comes with it you're laughing. Very rare to see a Mac sold with these, I've only ever seen one, and I didn't win it.
The MDDs came with 3 IDE buses, an ATA-33 for optical drives, an ATA-66 and ATA-100 for native support of up to 4 drives. The QS2002 only came with ATA-33 for optical and ATA-66 for two hard drives. IDE card or SATA card would get round this also.

Up to you again, the "Nap" feature used on the MDD made all the difference to me, between something that was too noisy at night to something bearable. Be aware, that if you leave the MDD downloading stuff overnight it'll still be noisy. Giving it a regular clean, especially arounf the airflow vents helps too.
The "windtunnel" effect happens when you really start to hammer the MDD. But this happens on all G5's too. These are real beasts of machines, with 4 drives, 2 G4s, big video card, USB2 card, SCSI card, wireless-n card, 2 DL DVD burners, they use a lot of power and need a lot of cooling ....

bertyboy, your posts are truly excellent in detail and value. Also a great refresher.

I had forgotten about the ADC/VGA ports possible pitfall (if you don't have a suitable Mac branded monitor with an ADC port you are restricted to VGA unless you buy an ADC to DVI connector). Although, my QS 2002 came with a GeForce 4MX 32 MB card with ADC/DVI connectors, so not having a suitable Mac monitor wasn't too much of an issue for me - I've since swapped this card out into my AD G4 533 DP and replaced the QS 2002's with a GeForce4 Ti 4600 128 MB which has DVI/VGA (thankfully) and I have to say, I haven't looked back, since.

About the Mac OS 9, 1.5GB RAM limit. I agree this is more than enough for OS 9, in fact you might even find certain Classic apps will behave better if there is less than 1 GB RAM on board and virtual memory is turned on. You can't use virtual memory with Mac OS 9.2.2 or earlier if you have more than 1 GB RAM on board.

Something I came up against, it may be important, then again it might just be my particular machine. That is both the AD 533 DP and the QS 2002 came with Gigabit Ethernet onboard, the AD 533's ethernet works at full speed when either booted into 9 or X, but on my QS 2002, ethernet only works for OS X. I needed to install a Kingston PCI card I had spare to get ethernet up when booted into 9 on the QS

> Important Notes-
> All QS 2002 models can boot OS9 natively, but like the MDD, they need a specific version
> of OS9.2.2 as a minimum. I used the MDD OS9 on mine. Works perfectly...

I struck this and did not have a suitable 9.2.2 install CD (bought my machines on eBay, no original CDs came with them and I only had a 9.1 OEM to my name)

I worked around this by ResEditing one file on the 9.1 install CD to accept the QS 2002 model as a suitable candidate for installing onto. I also rebuilt the 9.1 CD to included all Apple updates to 9.2.2 and burnt it fresh... Worked like a charm, but I'm going to need to revisit my notes to see exactly what I did, hopefully before I need to do it again :-[

Depends on the LCD display connector, if it's VGA or DVI.

Shouldn't be an issue for the MDD (DVI and ADC connectors). I'm not sure of the connectors on the GeForce4 MX and GeForce4 Titanium cards in the fast QS 2002's My 800MHz was the cheap end with a Radeon 7500. If the GeForce4 card has DVI, you should be fine.

If the LCD display has a VGA connector, there are plenty of DVI-VGA adapters for Mac out there, about £5 on eBay, it may even come with your MDD / QS2002 (it definitey came with them originally), I have a stack - got yet another 2 with my Mac Pro so we'll be able to sort you out if there's a drought on the market.

VGA isn't that bad, you're just limited to 1920x1200 (I think), Wikipedia might be a good way to find the limits.

If the the Mac you buy has a DVI/VGA card or DVI/DVI card installed, you are sweet to go (!).

Avoid if you can ADC/VGA cards these are real PITA. (a) Because they are Apple proprietary and (b) even Apple has ditched this AFAIK. It didn't "catch on". - If you get a Mac that has the ADC/VGA card on board you have to either (i) Get a monitor that supports ADC or (ii) Get an adapter for the ADC to convert to DVI (these cost around $80 AUS down this way) Or (iii) get an LCD display that also supports VGA and use analog display only.

Be aware that G4s of this period (the DA's thru MDD's), there is a good chance there may be ADC on board (even if the seller has swapped it out just to get rid of it). However, there were also ADC/DVI cards and these are OK. At least you will be able to use the DVI port in a new LCD from one of those.

A G4 Mac with a DVI capable vid card onboard should be a priority...

Look for a G4 with DVI/DVI, DVI/VGA or DVI/ADC but avoid if possible ADC/VGA otherwise its more outlay or analog only.

(!) One caveat here and this is a tip. Watch out for sellers installing swapped out cards from much earlier G4s even if they do have DVI ports. Esp. Rage 128 cards, these were very common in the earlier G3/G4s, they are 16MB and do not support modern wide screen displays, they are 4/3 aspect ratio only.

"Let the buyer beware" is an old adage that is so true today. So take care.

Final words -
If you're going to max out RAM, the DDR in the MDD is pennies next to the RAM required for the QS. Not an issue if it comes fully loaded. The DDR sticks came in sizes up to 2GB, you only want the 512MB sticks so they're quite cheap. The PC133 RAM for the QS only came in sizes up to 512MB, which is what you want - and so does everyone else.

A side effect of the "Nap" feature, is that the fans actually speed up (and get louder) for about 3-4 minutes while the temperature is reduced. Once the CPU is cooled, the fans are relatively quiet - but still louder than the other Macs.

60 euros was a good price for a FW800 MDD, even if it had only one processor (honestly, avoid uni-processor). It's a good sign that prices are quite low in Germany, but mid-week sells on eBay always are cheap, unlike Saturday / Sunday evenings which get the highest prices.

I'd be extremely impressed if you got a MDD / QS2002 within a few days of looking, took me nearly 2 months to find a PMG5 for the right price.

> Soon I'll be able to judge how noisy the MDD really is because my fiancé found
> a good offer on ebay yesterday and we bought it.

Congratulations. Actually I'd be interested in your opinion on this also. So please report back with your findings.

> Anyway, I need your help with a few questions:
> - 768 RAM is few. I want to upgrade to 2 GB.

Be aware, that if you intend running native "Classic" apps booted into OS 9.x, that there is a 1GB ceiling for *actual* RAM before virtual RAM becomes unavailable, and that some Classic apps will prefer to run with virtual memory turned on. You could find that you get better performance from classic apps if virtual memory is turned on. Once you introduce 1GB or more RAM to Mac OS 9.2.2 or earlier, virtual RAM will not be available to classic apps that are optimised for VM to be on.

This may or may not be an issue for you.

> What are the exact specifications of the RAM I need? Anything I should be
> aware of? Does it have to be RAM from Apple or will any model work?

Any _compatible_ make of RAM for your MDD will do.

> What could the Ultra SCSI port be used for? Is Ultra SCSI compatible with the *old* SCSI standard?

Its backwards compatible, but you might need an adapter to connect older devices. I believe that using older devices with slow the overall SCSI side down to the speed of the older device. Again this may or may not be an issue for you.

> What would be the max. graphics card I can put into this beast? Any idea about the prices?

(AFAIK) the "max graphics" card is what I have introduced to my QS 2002; a GeForce4 Ti 4600 128 MB AGP card (which was an option for your model) see this link for specs on your Mac:
http://www.everymac.com/systems/apple/powermac_g4/stats/powermac_g4_1.0_... Can't remember what I paid for this, I purchased it on ebay and it was an Apple ROM type card (not a cheap flashed PC card).

Awesome.

768 RAM is few. I want to upgrade to 2 GB. What are the exact specifications of the RAM I need? Anything I should be aware of? Does it have to be RAM from Apple or will any model work?

The minimum RAM should be PC2700 DDR. PC2700 is also known as DDR333. According to Crucial it can also take PC3200 - which is also known as DDR400. These are 184-pin memory DIMMs, they have just the one notch in the sticks. And you want the 512MB sticks, they come in a variety of sizes u to 2GB sticks, but you can't use anything larger than 512MB*.
There is also PC1600 and PC2100 DDR which is too slow to use, they were used in other Macs.
The PC2700 and PC3200 DDR RAM you want are about the same price new from Crucial, about £16 for 512MB for the PC2700 and £18 for the PC3200. You won't get any benefit from the speed increase of the PC3200- your RAM bus speed is 166MHz.
The MDD comes with 4 RAM slots, you don't need pairs of RAM or anything like that, fill any slots with whatever size you want.
eBay prices for memory tend to be about 50% of the new price for the stuff in demand. If you buy from there, make sure it's Non-ECC, Unbuffered - this is essential. 512MB sticks are not much in demand (except by MDD owners of course), since others are looking for 1GB or 2GB sticks, so you should get a good price. Avoid anything classified as "Server" RAM. Server RAM is always buffered and has ECC, it will not work at all.
Any good brands will be fine, Crucial (manufactured by Micron) or Kingston will be fine. If you're going to run OSX 10.4 Tiger, be aware Tiger got very fussy about memory quality, Leopard is even more so, then get Crucial / Micron / Kingston.

What could the Ultra SCSI port be used for? Is Ultra SCSI compatible with the *old* SCSI standard?

Just means you can use any SCSI drives internally - and externally. Don't go out of your way to buy SCSI drives to use, they cost more. Backwards-compatible like already said.

What would be the max. graphics card I can put into this beast? Any idea about the prices?

Stick with the Radeon Pro 9000 64MB for now. It'll be fine unless you're trying to run FPS's that require OSX 10.4 or later. Like said previously, you can use a variety of Radeon and nVidia cards. Of course, with a TFT monitor you'll have to make sure any new card can take the display. Replacement cards aren't cheap when they come up, neither is the Radeon Pro 9000 when it comes up, it fetches nearly the same as you probably paid for the whole MDD.

The Pro Speakers - Yes, the MDD has the port for those speakers - which I also have - the port is the very bottom port on the back, it also has regular speaker ports too. My PMG5 doesn't have the necessary port though (grrr). Just for info, there are adapters available, but they cost more than a new set of speakers. Apple also released these speakers with a USB connection - for use with the G4 Cube, which I also have - they require their own power supply.

I've already uploaded the full MDD OS9 install (OS and Aplications). It's International English, if that's OK ?
It requires you to install a version of OSX first - 10.2 or later, boot from it, and then mount the "OS9 General.dmg". Then drag all the contents to the MDD disk you want to run OS9 (or Classic) from. This is (roughly) how it was installed originally on the MDD - as a partial restore from within OSX, there was no OS9.2.2 Install CD/DVD.
Remember the rules about OS9 can only boot from a disk partition of less than 192GB - not an issue with the disks that came with the MDD.

The disc image is here.

There are a few firmware upgrades for various parts of an MDD, none essential, but I'll dig them out later (got to take my 9 month old daughter out for some crawling in the sun). I've also got all the updated Radeon drivers, again later.

I did consider trying to image and upload the two original MDD install DVDs, but they're enormous, maybe too big for MegaUpload - and of no value if you're going to install 10.3 or 10.4 (or 10.5).

All excellent news. It's even better when you've had someone who looked after the Mac before you. I bet they've applied all the firmware updates required, but here they are - well just one. I was sure there was a SuperDrive firmware update to allow the 2x DVD-R drive (Pioneer DVR-104) to use 4x media - it just meant it burnt them at 1x. But a big search at the Apple site, even using Google only shows the update for PMG4 DA, QS and QS2002.

Still the firmware update comes in an OS9 and OSX flavour:
http://docs.info.apple.com/article.html?artnum=120171

http://docs.info.apple.com/article.html?artnum=120186

I just had a thought anout the RAM upgrades, should have mentioned it earlier, PC2700 and PC3200 are suitable, but the RAM in the Mac MUST all be the same. Don't mix PC2700 and PC3200.

I'm going to check my SuperDrive firmware downloads to see what Mac they are for. Let us know what SuperDrive your new purchase has. With OSX 10.4.11 you can take almost anything, you'll only be limited on the burn speed because of the ATA-33 connector.

Of course, with only 2 hard drives, you could move the optical drive ribbon to the ATA-66 or ATA-100 bus and get really fast speeds. I didn't bother, 8x has worked perfectly for me to now in ATA-33, if I need faster I have a Mac Pro and a PMG5.

Firmware;
Open the System Profiler. Should open on "Hardware" by default, if not choose it. In there is "Boot ROM version", should tell you the version you currently have. compare it to the detail in the previous links. I'm saying it's not essential, but read the info in the linked pages to see what it fixes.

RAM:
Firstly, PC2600 is PC2700 so don't worry. It's DDR-333 which is the important bit. Here's the maths to show how they are the same ....
You have a bus speed of 166MHz.
DDR RAM on this should (all) be DDR-333 (or faster). It actually runs at 166MHz too, but because it pumps data through at twice the rate, they call it DDR-333.
The data path is 64 bits wide.
So 166 (MHz) x 2 (for DDR) x 64 bits = 21,248Mbits/s max throughput.
21,248Mbits / 8 (bits per byte) = 2656 MB/s max throughput.

So the memory should be called PC2656 - it's just a rating of the max throughput. Most sellers advertise it as PC2700 or DDR333. Apologies for any confusion caused. I have Crucial PC2700 in my MDD, shows up as PC2600 as well.

The "U" in PC2600U just means it's unbuffered - essential in memory for all Macs (except the Mac Pros)
The other nombers, "25330" I used to know, I think the 25 is the CAS Latency, 2.5. I'll find out the other if you REALLY want.

The QS2002 dual 1GHz you could have opted for only uses PC133 RAM, with the MDD you're on DDR333. It's some 2.5x faster for RAM. Kind of essential with 2 CPUs to feed data to / from.

The 256 Module shouldn't cause any performance issues. I lived with the same configuration - the 256MB was the DIMM that originally came with the MDD - for years and years, until it niggled me enough that I didn't have the full 2GB that I went out and bought another 512MB to replace it.

I'm a bit unsure about mixing the RAM, if it works with 2 PC2700 and 2 PC3200 then carry on and forget about it, but I did read ages ago on the crucial site about mixing speeds like this being a no-no. Maybe I should go back and have a look and post a link, If I'd known for sure that you could use PC3200 I could have sent you the 4 512MB sticks I pulled from my PMG5 - replaced with 8 1GB sticks.

Checked Crucial, they say it's OK, so enjoy the new RAM.

If you're still not convinced about the 256MB stick, put it in slot 3 (slots 0, 1, 2 & 3) so it won't be used until you really have to.

Good idea, start by checking all the jumpers, on all the disks.

Ideally ALL will be cable select.
And there may be one to delay spinning up by period of time (from when it gets power), but I've not seen that since SCSI disks.

Which brand / model is the 160GB ?

Is it attached to mid-cable or end-cable ?

I can't remember if this is the original cable, ie does it look identical to the other ATA ribbon for the hard disks ? God forbid that the previous owner may have put in an older ATA/33 ribbon. The older, slower 80GB disk may just get by, but the 160GB may get issues.

I'm sure that there are many more possibilities, but there is always the chance that the disk is cooked.

I'd try to change the Seagate to the ATA66 controller (and back to the ATA100).
Next you might try whether FWB Hard Disk ToolKit can "see" your device from OS9, if yes you can try to lo-level format it. At last, I would try to connect it to some Linux machine and run Gnome Partition Editor on it, in case some queer boot partition has been written on it.
If no utility can "see" the device on the bus, it is most likely dead.

I did think that the 160GB could have come from a hardware RAID, which might give it issues similar to those described. But FWB, and OS X 10.4 (and 10.5) Disk Utility should certainly be able to fix that.

It's just one of these things. I buy a fair share of 2nd hand Macs (but most are new), even 2nd hand RAM, but trusting all my data to a 2nd hand disk is just too much, you just never know what it's been through before you get it. If I've accumulated a disk in a 2nd hand Mac, the disk gets sold, on its own or in a Mac after a reformat and re-install.

@Bolkonskij: You reset the Cuda/PMU switch on the motherboard after introducing the new hardware? I usually do this now, if adding new drives or memory etc to a PPC Mac, its saved me some grief in the past.