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blizzard · May 10, 2003, 09:14 PM

Say, would I be able to buy a PPC 970 chip from an upgrade company and toss it into my G4/466? Or are the differences between generations just too great in this instance? I'm curious because I'm idly considering upgrading my old workhorse sometime soon...and a new 970 would be a fantastic addition, but somehow I seriously doubt even the upgrade companies could pull this one off...comments?

alex_kac · May 10, 2003, 09:31 PM

We just won't know. The MDD design may be in such a way that the logic board is completely independant from the CPU daughter-card allowing it to use the full DDRAM abilities of the MDD and work (taht would require the boot ROMs, etc... all to be on that same daughtercard as well as all controller chips that need to speak with it).

Its also possible that a daughtercard will work if there is a new controller chip that converts the 970 speak to the way the rest of the logic board expects to talk to the CPU.

Its engineering. Yes, it can be done. Question is - can it be done cheaply enough to market?

kupan787 · May 10, 2003, 10:29 PM

Originally posted by alex_kac:
We just won't know. The MDD design may be in such a way that the logic board is completely independant from the CPU daughter-card allowing it to use the full DDRAM abilities of the MDD and work (taht would require the boot ROMs, etc... all to be on that same daughtercard as well as all controller chips that need to speak with it).

Its also possible that a daughtercard will work if there is a new controller chip that converts the 970 speak to the way the rest of the logic board expects to talk to the CPU.

Its engineering. Yes, it can be done. Question is - can it be done cheaply enough to market?

The 970 has a different type of bus than the G4 (maxbus vs whatever the 970's bus gets called). So that right there could cause some issues, and make it impossible. But assuming that could be worked around, the 970's bus runs at 900MHz. Your G4 has either a 100, 133, or 167 MHz bus. So it wouldn't be worth it. The processor would be totally choked.

vasu · May 10, 2003, 11:19 PM

I thought the 970 ran at a 900Mhz DDR, so it's actually 450Mhz right?

Still even a new MDD is 167Mhz compared to the 450

-vasu

alex_kac · May 11, 2003, 12:44 AM

Originally posted by kupan787:
The 970 has a different type of bus than the G4 (maxbus vs whatever the 970's bus gets called). So that right there could cause some issues, and make it impossible. But assuming that could be worked around, the 970's bus runs at 900MHz. Your G4 has either a 100, 133, or 167 MHz bus. So it wouldn't be worth it. The processor would be totally choked.

I never said it was efficient. Just possible.

Technically possibly, that is. AND, things can be designed in such a way that the current MB already is ready for the 970 bus and just downthrottles to the G4's bus with a translator chip. Its POSSIBLE, though unlikely.

The point I was trying to make was that until the 970 ships and we can actually see it in action on a PowerMac, we just won't know.

kupan787 · May 11, 2003, 01:07 AM

Originally posted by alex_kac:
Its POSSIBLE, though unlikely.

This is where I am not sure. The 970 bus is unlike the G4, P4, or AMD buses today. I am not just talking about the speed of the bus, but the actual design of the bus. Part of it is that it has a bidirectional bus where as the P4, G4, and AMD use a unidirectional bus (I may have that backwards, but the 970 bus has separate read and write pipes, while the other buses have a single pipe for both). It MIGHT be possible to make some kind of translation from the 970 bus to MaxBus. However if that is even possible, we are talking about a speed hit for the translation.

And about the comment that the 970's bus is double pumped, well so is the G4s (everythign except the memory bus is double pupmed on the G4). So we are compaing 333 to 900. That is still 3 times greater. However since the 970's bus is based on clock speed (it runs at half processor), so as the 970 gets faster (2GHz, 2.5GHz) so does the bus (1GHz, and 1.25GHz respectivly). So maybe you could get a 1.2GHz 970 upgrade card (with a bus running at only 600MHz so only double todays G4 bus). But liek I said, this all assumes they can get some kind of translation done.

A similar discussion was done over on Appleinsider. I think someone, with more knowledge than me, said that it was basicly not possible, so don't get yoru hopes up.

Agasthya · May 11, 2003, 02:44 AM

Originally posted by blizzard:
Say, would I be able to buy a PPC 970 chip from an upgrade company and toss it into my G4/466? Or are the differences between generations just too great in this instance? I'm curious because I'm idly considering upgrading my old workhorse sometime soon...and a new 970 would be a fantastic addition, but somehow I seriously doubt even the upgrade companies could pull this one off...comments?

The words "Apple" and "upgradeable" should not be used in the same sentence. Apple is gonna pull out all the stops on this one to make sure people need to buy G5s.

But really, its going to be based on totally new stuff and probalby even a new chip connector, I don't think that its doable. DDR400 RAM, faster Bus, whole new chip architecture...don't think so.

OreoCookie · May 11, 2003, 09:08 AM

No, this will not work. Both use very different CPU interconnects at very different speeds. There is no way that you could pop in a PPC970 into a G4 without having to build a ?translation' chip. But this would be a huge performance hit since

1. the translation chip itself will be a performance penalty

2. the PPC970 will never be saturated as far as bandwidth in concerned.

In this case, it's not Apple's ?fault'. But it's not going to work, I'm afraid.

DrBoar · May 12, 2003, 01:47 AM

There was a PPC upgrade of the IIci. And the 601 really is even more different to the 68030 than the 970 to the G4. Putting a 100 MHz 601 9n the IIci did not make it a 7500/100 by far. Dog slow bus, slow SCSI no PCI and thus no IDE,USB,FW or fast graphics....

Throwing in a 1GHz or faster 970 in a G4/400 will be the same thing. So I really thing it is a academic quietion if there will be 970 upgrades or not. What I hope for is that the 970 will drop the price of high end G4 upgrades

kupan787 · May 12, 2003, 11:52 AM

Originally posted by DrBoar:
There was a PPC upgrade of the IIci. And the 601 really is even more different to the 68030 than the 970 to the G4. Putting a 100 MHz 601 9n the IIci did not make it a 7500/100 by far. Dog slow bus, slow SCSI no PCI and thus no IDE,USB,FW or fast graphics....

Throwing in a 1GHz or faster 970 in a G4/400 will be the same thing. So I really thing it is a academic quietion if there will be 970 upgrades or not.

Not really. The bus on the IIci is a lot closer to the original PPC bus (based on how it works) than the 970 bus is to the G4 bus. Forget everything you know now, the 970 is a totally different beast.

JB72 · May 12, 2003, 07:33 PM

Originally posted by kupan787:
A similar discussion was done over on Appleinsider. I think someone, with more knowledge than me, said that it was basicly not possible, so don't get yoru hopes up.

Yeh it's not going to happen. Especially from Apple.

I have an MDD, so I won't be lucky enough to jump right on the 970 bandwagon. But I like to think that I'll be able to go to a 970 machine once it "matures" and there are some 64 bit apps to use.

dfiler · May 13, 2003, 11:55 AM

Originally posted by agasthya:
[B]The words "Apple" and "upgradeable" should not be used in the same sentence. Apple is gonna pull out all the stops on this one to make sure people need to buy G5s.

What's your agenda?

Of the Macs that I've owned, all four had upgradable CPUs, storage, memory, and display systems. All included high-speed internal expansion slots along with industry leading external expansion options. This includes machines from before and after the PPC transition as well as one clone.

Expansion? Almost all desktop macs have been upgradable to the next generation CPU. I'm not saying this will be the case with the 970. Rather, that extrapolation from previous events shouldn't lead one to conclude that 970 upgrades won't be available.

<speculation>
In my opinion, the technical hurdles aren't insurmountable. Hell, anyone remember SCSI driven color displays for the Mac classic? Or how about the NuBus based RAM? Yet I don't expect to see 970 upgrades for G4 machines. The new 970 boxes will likely offer significantly better performance over an upgrade with little additional cost.
</speculation>

Evangellydonut · May 14, 2003, 09:46 AM

Considering how much difference there will be in terms of pins on the CPU, i wouldn't count on any upgrades for probably 2 years after 970's initial release if ever at all (and I'm willing to put $$ on the later).

In theory, everything is possible, right? someone can be crazy enough to come up with a co-processor that converts all PPC assembly in real-time to x86 assembly and put a P4 CPU on the same board and make it compatable with the current G4s (which is somewhat similar to what AMD did with their Athlon, which breaks down x86 instructions to microcodes that are much more like the G4 instruction set than the P4's)...Upgrading G4s to 970 is as far-fetched as that if not much more so. For starters, it's a 64-bit chip, so there'll be 64 pins for Address instead of 32, and getting around that will be quite a challenge...if it does get accomplished, the usage of a latch of sort to send out address 32bit at a time will almost effectively decrease the CPU's bandwidth by 50%, not to mention all sort of delays introduced by the latch itself.

I got a G4/450 Sawtooth 'n held out on buying a new Mac 'cuz of this 970 deal...I'll be one of the first to order my mid-level tower when the new box comes out

blizzard · May 14, 2003, 11:03 AM

Righto, guess I'll look at dual 800s G4s or a single 1.2 then

Thanks for the replies!

Staatkunde · May 19, 2003, 12:56 PM

I agree with Agasthya, Apple will do whatever it takes to get you to buy a new machine. They are down to 2.2% of the market and have lost 31% of their desktop sales. They really need everyone to buy new desktops. My vote goes towards total incompatibility.
-Mark

JB72 · May 19, 2003, 05:11 PM

Originally posted by Staatkunde:
They are down to 2.2% of the market and have lost 31% of their desktop sales. They really need everyone to buy new desktops.

I'm sure they are planning on reversing that 31% somewhat with the release of Final Cut Pro 4. They've put enough effort into it. Further, of course, with the release of 970 PowerMacs and Panther.