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blackwind · Aug 22, 2003, 11:30 PM

Hello. I was just wondering about the costs of Apple producing the G5 motherboard.

I just realized that the Power Mac G5 has three different motherboards for each version.

The 1.6-GHz G5 has a "crippled" motherboard with only 4 RAM slots and normal PCI slots.

The 1.8-GHz G5 has a motherboard that lacks connectors for a second processor.

The Dual 2-GHz G5 has the fully-equipped motherboard.

Would it not be less expensive for Apple to produce a single type of motherboard considering that Power Macs are mass produced? Or is reducing the feature set of the motherboards of less-expensive Power Macs actually less expensive?

Eug Wanker · Aug 23, 2003, 12:08 AM

Two motherboards.

Supposedly the 1.8 and dual 2.0 use the same motherboard. The 1.8 just uses a board in which the socket, etc. are not included for the second CPU.

But if you were VERY careful with a soldering iron, I suspect you could build a dual from a single's motherboard.

jclarkv · Aug 23, 2003, 05:37 AM

Plus, I've just gotta believe that Apple did this analysis before they decided on configurationsand that the cost difference just wasn't that significant.

MaxGuru · Aug 23, 2003, 01:59 PM

Originally posted by Eug Wanker:
But if you were VERY careful with a soldering iron, I suspect you could build a dual from a single's motherboard.

Go ahead. You first. I'm right behind you.

Eug · Aug 23, 2003, 04:13 PM

Originally posted by MaxGuru:
Go ahead. You first. I'm right behind you.

After you my friend. (I'm not a solderer-type.)

Hydra · 04:31 PM

I don't think the real problem is so much adding a second socket as it is where the heck do you get one of them newfangled PPC970 CPU's

You can solder till the cows come home but it may be a long while before you can find anything but air to put in that socket

As to the production costs. You get the feeling that the engineering team built the 3 models of the G5 to a different price structure than what we see now and the marketing people changed everything. You have a bottom line model with a completely different motherboard (inferior RAM and not as cutting edge PCI-X) that is only a few hundred dollars less than the next model up (esp. if you spec it the same). I just get the feeling it would have been cheaper for Apple to just have one MB with a range of speeds available to separate them all. Not to knock those who bought the 1.6 (it is far better architecturally than any G4 before it) but wouldn't their decision have been much easier if it shared the MB with the 1.8 and 2.0?

-Jerry C.

chabig · 09:04 PM

Even though the 1.6GHz model has PCI slots and the 1.8 and 2.0GHz models have PCI-X, I would bet that the motherboards are the same and that the custom chips that manage the PCI buses are pin compatible with each other. That way you populate a common board with different components for different configurations.

Chris

Hydra · Aug 23, 2003, 04:37 PM

Originally posted by chabig:
Even though the 1.6GHz model has PCI slots and the 1.8 and 2.0GHz models have PCI-X, I would be that the motherboards are the same and that the custom chips that manage the PCI buses are pin compatible with each other. That way you populate a common board with different components for different configurations.

Chris

Not really. It seems from pictures that the 1.6 MB is really different. Has less room for the RAM sockets too. The 1.8/2.0 has 8 RAM sockets and the 1.6 has only 4. The interesting thing is that the 1.6 MB looks like it doesn't fill out the case as much as all the 2.0 photos I have seen. I could be wrong, however.

-Jerry C.

chabig · Aug 23, 2003, 05:21 PM

Jerry, you may be right. I haven't taken a close look at the 1.6 motherboard.

Chris

Eug Wanker · Aug 23, 2003, 05:57 PM

Like I said earlier, it appears the 1.8 and dual 2.0 are identical boards, except the latter has the extra socket installed. The 1.6 has a physically incompatible board.

kupan787 · Aug 23, 2003, 06:28 PM

Originally posted by Eug Wanker:
Like I said earlier, it appears the 1.8 and dual 2.0 are identical boards, except the latter has the extra socket installed. The 1.6 has a physically incompatible board.

Having not seen the PCI area up close, I know there is room for the ram and processor "ports" to be soldered on. I don't know the technical term, but you can see EXACTLY where the extra ram and processor slots goes (there are little grey dots forming bars). If I had photoshop here, I would circle the areas (but alas, I am away form hom)

So how sure are you that there are two boards, and not just one? What makes the 1.6 a "physically incompatible board"?

Hydra · Aug 23, 2003, 06:56 PM

Originally posted by chabig:
Jerry, you may be right. I haven't taken a close look at the 1.6 motherboard.

Chris

I may actually be wrong and you may be right after all. After further side by side review of the photos of the 1.6 I found in this board http://www.spymac.com/forums/showthr...threadid=37107 with dual 2.0 photos I found what looks like little areas on the MB of the 1.6 where the extra RAM sockets go and they actually look alike except for the RAM sockets themselves. I guess my dual 2.0 prejudice led me to believe they really were different.

-Jerry C.

Eug Wanker · Aug 23, 2003, 07:05 PM

Hmmm.... You guys may be right. Makes you wonder what would happen with DDR400 RAM in the 1.6.

kupan787 · Aug 23, 2003, 08:34 PM

Originally posted by Eug Wanker:
Hmmm.... You guys may be right. Makes you wonder what would happen with DDR400 RAM in the 1.6.

My guess, it would run at 333MHz speeds (just like PC133 ram on a 100MHz bus, the ram runs slower). I bet the system control (is that what it is called) controls the ram speed (with jumpers maybe?). The ram slots are all the same (just like in my 100 vs 133 example), so something is just telling the ram to run at a certain speed.

I know with older mac models, that you could "overclock" the PCI speed, the FSB speed, or the processor speed, depending on jumper settings. I remember reading over on the xlr8yourmac forums of someone overclocking their sawtooth's 100MHz bus up to 133MHz. But that is back in the day when the FSB speed was the same as the RAM speed. Now with the G5, the RAM speed != FSB speed. The FSB in the 1.6 runs at 800MHz. The ram runs at 667MHz (right? 333 double pumped) So I don't know if you can change just the RAM speed with a jumper, without effecting some other component.

But who knows, and who will be the first experimenter

Eug Wanker · Aug 23, 2003, 08:44 PM

The RAM in the 1.6 runs at 167 MHz at DDR = 333 MHz

It is run in pairs in dual channel mode = 667 MHz (sort of).

Yeah, I wonder if it's just a bunch of resistors telling it to run at 667 MHz instead of 400 MHz.

Hydra · Aug 23, 2003, 09:25 PM

Interesting new MB photo here : http://www.spymac.com/gallery/

What is that funky j-shaped thing on the back of the MB? Some kind of heat-pipe to cool the chips on the back of the board and not in the air-stream? I wish Apple would just go ahead and ship me my Dual G5, I need to stop hanging in these boards looking for info

-Jerry C.

chabig · Aug 23, 2003, 09:32 PM

I just took another look at Apple's PowerMac G5 Technical overview document. It doesn't address the differences between the models. But from an economic standpoint it just wouldn't make sense to me to manufacture a unique logic board for the low end model that has no future. It might make sense to do so for the high end model where you can charge more and earn a higher margin, but not for the low end.

The memory in the 1.6 GHz model is 333DDR. In the faster machines it's 400DDR. I bet that the controller isn't much different for those two memory types. And since PCI-X is a superset of PCI I bet that its controller can be virtually the same as well. There is probably some jumper combination that sets the Advanced System Controller and PCI interface chips appropriately for each model.

We'll know more soon.

Chris

ASIMO · Aug 23, 2003, 11:23 PM

You guys disappoint me. Where the hell is all the bitching and whining? Are you sharing a bong?

kupan787 · Aug 23, 2003, 11:35 PM

Originally posted by ASIMO:
You guys disappoint me. Where the hell is all the bitching and whining? Are you sharing a bong?

No bong here, just happy about the prospects of the G5. Why should I bitch?

Eriamjh · Aug 24, 2003, 06:52 AM

In all likelyhood, all G5 models share the exact same motherboard, however, it is "populated" differently between models. This is the most cost efficient way to go.

I have seen pics of the 1.6 and it has the vias for mounting the extra 4 DIMM slots that the 1.8 and 2.0 have. There are chips and support components left off the board where the second processor would be.

How Apple can have one board with PCI and PCI-X I do not know, but as stated, it is either a pin-for-pin compatible controller alternately populated or there are two controller areas and one is used for PCI and the other is used for PCI-X.

Apple's documentation has been absolutely devoid of mentioning anything technical about the 1.6 and 1.8. They only go into the duals as if all G5s were duals.

In conclusion, I think the singles are truly crippled versions of the 2.0 with most components left off. There will not be a way to upgrade them to be duals.

However, if Apple received enough dual orders, perhaps they will consider dropping the single models and moving to all dual models?