What is the real cpu limitation? could a new CPU Upgrade come out in the future?

[macStuff]

given that companies were making cpu-upgrades 20 years ago...
is there a technical possibility that a company could leverage new technology to create a NEW modern CPU Upgrade for powerPC macs in the future?
(for hobbyists)
 
can you imagine a classic mac with SataII disk speed; + a 3Ghz processor?

[lepidotos]

It's certainly possible, but the massive variation between, say, different G4 models even within the same year and subcategory (a 450MHz Sawtooth like mine has at least two different major variations, where the earlier can't do multiprocessing and the later can) means that each individual upgrade either has to target the lowest common denominator or be the best upgrade it can be... for about 500 computers. I would certainly love for at least the latter to be the case, and Motorola are still making 750FX/CX/GXes, and both 7450 and 7457 chips are at least available as NOS. I just bought a definitely NOS 7455 to try to make a homemade 750MHz upgrade board (the chip is rated for 1GHz but I assume that's for a 133MHz FSB) so I'll report back on that, but G3 (and Yikes? Since it's a G3 board, I assume using a 750 upgrade in it would just turn it into a, uh, G3 G&W) would probably be a more viable upgrade board target because there's less variation between computers. If the demand can be shown, then a run could probably be made. Amiga folks use 7457s pretty regularly so there should be some demonstrable demand for them.

[IIO]

any homemade processor card will run into the same problem which sonnet had when they tried to sell dual 1,8 and 2,0 GHz; the shit is getting too hot.

a quicksilver with dual 1,6 or the MDD dual 1,42 are pretty fast machines, SATA II is possible there, and if you add a protools farm and a 30" monitor you can work with that for the next decade.

[lepidotos]

any homemade processor card will run into the same problem which sonnet had when they tried to sell dual 1,8 and 2,0 GHz; the shit is getting too hot.

a quicksilver with dual 1,6 or the MDD dual 1,42 are pretty fast machines, SATA II is possible there, and if you add a protools farm and a 30" monitor you can work with that for the next decade.

Yeah, 3GHz is absolutely out of the question without, like, dry ice chucked in with it. But I could see a 1.4 upgrade, or even single 1.8, with proper cooling. An MDD or Quicksilver is the obvious choice, but it might not be as available as anything earlier given their reputation as the be-all end-all of the G4 series and thus the most versatile from a retro computing standpoint; looking on the 'Bay, I see sellers not shy about charging $260 and up for one, where I bought my Sawtooth for $36, and didn't have to pay taxes or shipping, enough to buy a GPU, new processor, hard drive, and keyboard and still have paid far less than for just a computer, with room to spare for getting a full set of RAM. Part of the reason is because of the higher demand, and part of it is because MDDs are more often sold by collectors/old Mac people rather than just anyone.
If there's any way to get the older machines on at least the level of a QS, it's worth at least running the numbers on, even if nothing ultimately comes of it.
Plus, this is just my seemingly entirely unique opinion, but I kind of think anything after the Graphite is kind of ugly. I realize that it being the better computer is all that matters, but it's still there.

[teroyk]

Yeah, 3GHz is absolutely out of the question without, like, dry ice chucked in with it.

I put that image before, but have to put again:

It is Quad-core 4Ghz, but sadly it is not anymore Mac OS 9 compatible.
Picture is from page: https://www.tori.fi/pirkanmaa/Steroid_eMac_83550382.htm

I don't think there is real cpu limitation, but I think more might help
CPU-card with 1 Gz CPU with 1 GB L2 write-back cache than Cpu-card with 4 Ghz CPU with 1 MB cache.

[IIO]

when i am not wrong, the dual 1.6 from sonnet also supports the pre-quicksilvers.

the single 1.7 encore works fine in a sawtooth. (for the duals you eventually have to overclock the bus speed(?), but the encore st works out of the box)

however, if you want a fast as possible computer you should not ask which case design looks better. take an MDD and put in a custom case and all is good.

and if it is all about clock speed, the quicksilver has the fastest option.

I put that image before, but have to put again:

4000 HP in a beetle chassis!

[lepidotos]

So I asked 68kMLA, and they said that there's currently no community PCB design out there for a G4 processor board, and no board designs from old commercial board upgrades that anyone's released. So I've took it upon myself to do it, since I was already in the early stages of another hardware RE for something else. If I make any progress on that, I'll be sure to share the gerber files. I have the 7455, just picked it up today, so that's one component down already. The folks over there even gave me a partial checklist to refer to.

[Angelgreat]

Modern CPU upgrades for the PowerPC Mac's? That be cool. It would make some hard to find upgrades more acessable. In addition, we could also make some new upgrades that weren't thought of back then. For example, making a G4 upgrade card for a 68k mac or making a replica sonnet harmoni g3 but with a G4 CPU or even a G5 upgrade to the eMac. Those would be cool.