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Power Mac G5 Developer Note

Sun Baked

Sun Baked

macrumors G5
Original poster
May 19, 2002
14,946
168
OK, we've been waiting for Apple to post the developer documents on the hardware page for awhile, they're here.

These should answer some of the nagging questions we had about the machine, and give a little better insight into the machines architecture.

---> New Documentation: Power Mac G5 Developer Note (Preliminary) (PDF)

General Hint...
 
Article Link
https://www.macrumors.com/2003/07/03/powermac-g5-details-processors-cooling-kb-codename/

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Oops.. someting is burning..

Well.. this means that if i use a version of Linux for PPC not having the "Thermal Control" implemented, i'm gonna smell burnt CPU ?

Sounds awful to me..
 
Re: Oops.. someting is burning..

Originally posted by Slaytanic
Well.. this means that if i use a version of Linux for PPC not having the "Thermal Control" implemented, i'm gonna smell burnt CPU ?

Sounds awful to me..
Click to expand...

No, afaik the fans run at full power if there is no thermal control. So rather "Ooops... something is brawling..." - still awful but at least not that awful as a burnt CPU was.
 
hmmm......... ATA 100 bus to control the superdrive. More than fast enough to run a standard PATA hard disk to use as a boot disk, and then you could RAID the other 2 SATA disks. (I do video editing and composting so I actually need the sustained thtoughput that RAID provides.)

I wonder if you could put a normal 80pin ribbon cable on there (one with two connections) and somehow mount a PATA disk in the space where the PCI-X cards go. Then conect the hard disk up as a slave and the Superdrive as master.

I know people will say just use an external firewire disk to boot from as its easier and doesnt wreck the case or (possibly) void your warranty, and that is probably what I'd do, its just an idea.
You could also replace the superdrive with a hard disk and put the superdrive in an external enclosure.
 
Does this imply that a single processor machine can be upgraded to a dual?
 
Looks like they're still not acknowledging the DVD-RW capabilities of the SuperDrive. And shouldn't it have Pioneer's A06, which does +R/+RW, too?

So instead of many buyers getting a G5 with SuperDrive, many will opt to save $200 and get a ComboDrive, and use the $200 to buy a $300 A06 aftermarket.

And this benefits Apple how?

They're shooting themselves in the foot if they don't acknowledge all four: -R, -RW, +R, +RW.

For someone who "likes options" (Jobs' famous quote when asked about using AMD processors), he sure doesn't like to provide his customers with any.
 
One thing I noticed is that the DDR RAM has to be installed in pairs in the G5. It usually won't cost you a lot more to get double of half the memory you wanted. (Ex. If you want 512 you have to get 2x 256) But it takes up two of your spots.

It was kind of unusual to see on Apple Website why they offered 2x 256mb instead of 1 512. At first I thought it was to save money.
 
Originally posted by bosskxx1
It was kind of unusual to see on Apple Website why they offered 2x 256mb instead of 1 512. At first I thought it was to save money.
Click to expand...

Probably because it's a 64-bit architecture and most RAM is designed to be addressed by 32-bit systems.
 
Originally posted by AtariMan
I wonder if you could put a normal 80pin ribbon cable on there (one with two connections) and somehow mount a PATA disk in the space where the PCI-X cards go.
Click to expand...

How about a 60GB laptop drive (2.5"). It would be easier to find room for a small drive. It'd be a bit slower than a 7200RPM drive, but would let you stripe the other two.

You'd need a cable/power adapter like, but they're easy to find:

C184-17705.jpg


link to catalog
 
There's big news here folks!

The largest DIMM supported is a two-bank DIMM of 2 GB using 512 Mbit DDR SDRAM devices. The maximum number of devices per DIMM is 16.
Click to expand...

This means that the G5 actually supports up to 16GB of RAM (2GB/slot), but Apple must not be able to find 2GB modules (heck, I can't find 1GB modules - where do they get them?).

Of course, if Apple is hedging on this as usual, it may support even more.
 
for bandwidth, not register size

Originally posted by ClimbingTheLog
Probably because it's a 64-bit architecture and most RAM is designed to be addressed by 32-bit systems.
Click to expand...

Standard RAM is already 64-bits wide (when you see NNNN x 64 in the part number, the "64" is the bit wide - 72-bit wide is ECC memory).

Apple (as well as most high performance Intel boards) use pairs of 64-bit wide memory DIMMs in order to transfer 128-bits per effective memory clock cycle. This is then passed up to the CPU on a narrower, but faster, bus. (64-bits at 167MHz for G4, 64-bits @800 MHz for P4, 32-bits at 1000MHz for G5)

It's unrelated to whether or not the CPU is 64-bit. Server systems carry the concept further, using memory in multiples of 4, 8 or even 16 DIMMs.
 
Originally posted by ClimbingTheLog
Probably because it's a 64-bit architecture and most RAM is designed to be addressed by 32-bit systems.
Click to expand...

Nope! Apple is essentially RAID-striping the memory to get the bandwidth out of it that they need.
 
Originally posted by testnull
This means that the G5 actually supports up to 16GB of RAM (2GB/slot) ...it may support even more.
Click to expand...

According to the PDF link above:

Processor Bus

The processor bus is a 800 MHz, 900 MHz, or 1 GHz bus connecting the processor module to the U3 IC. The bus has 64-bit wide data and 36-bit wide addresses.

36-bit physical addresses implies that the chipset has an absolute max of 64 GiB. (The G5 supports 42-bits, so a different chipset could support even more.)

Apple probably decided that 64 GiB will last until they have to do a new chipset for the 980. :D
 
The G5 is a nice architecture. I'm impressed with Apples Design Chips thusfar. As long as the mobos are reliable they have a winner here.

As for Dual Channel Ram...it's the only way to maximize the memory throughput to hit 6.4BGbps. Without giving up your Arm and Leg for memory.

Hopefully the Vaper PPC 980 will have a buit in memory controller based on a scaled POWER5. This would allow the memory throughput to scale per Processor right? Opterons have that advantage now.

After seeing $700 Opteron boards(Gigabyte Dual) that over %80 of what these boards offer..I'm starting to think Apple has priced these machines quite fairly.
 
I was wondering about the single versus dual thing. The processors seem to take up a lot of space, so with only one, would there be a big gap? Would it look uglier inside? Maybe you could put a HD or something in the space.
 
Originally posted by testnull
Nope! Apple is essentially RAID-striping the memory to get the bandwidth out of it that they need.
Click to expand...

Ah, memory interleaving. Every few years they decide to do it, then decide not to do it, then decide to do it...
 
dual bank memory requirements

Actually, I've always found it interesting that Apple has traditionally led the charge to dual bank designs. I've been selling and repairing both macs and PCs since the early 90s, and it always seems like Apple would go dual bank (for the massess) before PC companies.

Remember 30 pin SIMMS? Apple had those things paired up in 68040 machines pretty early on.

Then the industry switched to Single 72-pin SIMMS. When the first powerPCs came out, they required paired 72-pin SIMMS.

The DIMMS, now Paired DIMMS? <grin> I can't wait to see what's next...

128-bit QIMMS? that'll be interesting because I've heard QIMM used in a gross naughty joke kinda context before... ;)

They'll have to come up with something else, I bet... <grin>

Dharvabinky
 
Originally posted by nuckinfutz
Hopefully the Vaper PPC 980 will have a buit in memory controller based on a scaled POWER5.
Click to expand...
Slightly off-topic but thank you for calling the 980 what it is, vapor-ware!
 
Which keyboard to get?

I've been thinking of replacing the mini keyboard that came with my tray-loading iMac. Does anyone have an opinion on the new keyboards (the ones that I heard come with the eMacs) versus the Pro keyboard? (Personally, I thought about getting one of the Macally keyboards, but my wife is vetoing that since she wasn't able to test it in person)
 
Re: Which keyboard to get?

Originally posted by onnimikki
I've been thinking of replacing the mini keyboard that came with my tray-loading iMac. Does anyone have an opinion on the new keyboards (the ones that I heard come with the eMacs) versus the Pro keyboard? (Personally, I thought about getting one of the Macally keyboards, but my wife is vetoing that since she wasn't able to test it in person)
Click to expand...

Get an Apple Extended Keyboard II at a yard sale and hook it up with a Griffin iMate - you won't be sorry.
 
Originally posted by bikertwin
Looks like they're still not acknowledging the DVD-RW capabilities of the SuperDrive. And shouldn't it have Pioneer's A06, which does +R/+RW, too?

So instead of many buyers getting a G5 with SuperDrive, many will opt to save $200 and get a ComboDrive, and use the $200 to buy a $300 A06 aftermarket.
Click to expand...

That's exactly what I'll be doing. If the A06 isn't included, I'm saving the money and getting either an A06 or a Sony DWU10A or a Sony DRU-500A. I want both plus and minus. And actually, I have seen the DWU10A for only $150 or so.

The only question is, does OSX support these drives? It should, since I believe the command set for these drives has been standardized. Also I understand some of the iMacs shipped with the DWU10A at one time or another, which would imply support. Anyone know for sure if the Sony drives work with OSX?
 
I'm not sure the keyboad thing is a foregone conclusion. The G5 is the only mac with usb 2. Why use a keyboard that only acts as a usb 1 hub (as stated in the keyboard description in the tech note)? I think there will be a new pro keyboard which gives you the option of plugging the keyboard into one of the G5's usb 2 ports... Of course, against my own argument, perhaps this is why they are including a usb 1 port on the back... Plug your keyboard into it and you get an open usb 1 port close to hand (once you have plugged your usb mouse into the other one on the keyboard), as well as the usb 2 port on the front of the G5...

I guess I just want to believe that there will be a new pro keyboard/mouse.
 
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