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So I bought a Motorola XC7455A-RX1000PF...

lepidotós

lepidotós

macrumors 6502a
Original poster
Aug 29, 2021
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Marinette, Arizona
I'm going to try installing it in my Power Mac G4. I'm assuming the 1GHz rating is not for 100MHz busses, so what is it for? 133? I assume so and accordingly say I'll build a 750MHz upgrade (or 900 if I get around to installing the DIP switches), but I have no real idea, since every time I try to download spec sheets I can never find one. Does it even matter? I just want to know what to expect. It should still be an upgrade even if it keeps my computer at 450MHz due to the L3 cache.
 
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The 'RX1000' means the chip is rated for 1000MHz (1GHz). It would probably work at 1.2GHz, and maybe 1.5 if you crank up the voltage and keep it cool. Which computer are you going to put this in? It requires soldering to attach the chip to a circuit board. There are some ebay "reball" companies that could help. I saw there are also a few people on the 68kmla forum that solder stuff like this. Good luck and let us know how it turns out!
 
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ervus said:
The 'RX1000' means the chip is rated for 1000MHz (1GHz). It would probably work at 1.2GHz, and maybe 1.5 if you crank up the voltage and keep it cool. Which computer are you going to put this in? It requires soldering to attach the chip to a circuit board. There are some ebay "reball" companies that could help. I saw there are also a few people on the 68kmla forum that solder stuff like this. Good luck and let us know how it turns out!
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My Sawtooth. I considered my iBook for a second but I'm concerned about the thermals, it's already 900MHz, and the Mobility Radeon 7000 it has seems like a pretty major bottleneck. It seems to be an earlier computer since it has the green power LED, but on the back there's a copyright year of 2000 and every serial number checker I consult on it suggests it was built in April 2000.
Thanks, and I will. I'll do it from the computer itself if it turns out alright.
 
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I was wondering if you've made any progress on this. Did you find a way to install it in your sawtooth?
 
lepidotós said:
My Sawtooth. I considered my iBook for a second but I'm concerned about the thermals, it's already 900MHz, and the Mobility Radeon 7000 it has seems like a pretty major bottleneck. It seems to be an earlier computer since it has the green power LED, but on the back there's a copyright year of 2000 and every serial number checker I consult on it suggests it was built in April 2000.
Thanks, and I will. I'll do it from the computer itself if it turns out alright.
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That's just not gonna work. The 7455 uses a completely different BGA with more pins so there is no chance, that CPU could only be soldered onto a Quicksilver or MDD CPU card but those were offered with the same and better from the factory. The L3 cache is also on a seperate chip from the CPU itself.
 
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yeahhhhhh... it's impossible with the CPU card that the sawtooth G4s come with. first off, you have a 483 pin CPU with the 7455 as opposed to the 360 pin CPU with the 7400. second, they're going to be electrically incompatible anyway and you don't have a choice other than a 7410 if you want to use the original CPU card. hate to break it to ya but that's how it is. i even tried putting a dual 800mhz 7450 (with utter regret, i sucked at soldering) into a sawtooth and it... never really worked. imo the best you can do right now is get a dual 450 card and overclock it to 500mhz. i have one in my sawtooth and it works fairly well. keep in mind not everything will use multiprocessing.

speaking of 7455s and chip swaps, i just got my hands on a single processor 800mhz G4 quicksilver 02 (no L3 unfortunately) and i might swap its 7450 with a 7455... i'm obviously no expert so this could possibly be a failure too. might see if someone else can do it for me.
 
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ervus said:
I was wondering if you've made any progress on this. Did you find a way to install it in your sawtooth?
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Above two posters are right, so I've decided to look into getting a new PCB printed. 68kMLA didn't have any designs that I could just have made, so I'm gonna make one myself.
 
That sounds like quite a project. Did you get the schematics somewhere?
 
Schematics and PCB layouts are not quite the same thing. If you don't have either they you need to completely reverse engineer an existing design.

You could try contacting Sonnet, OWC, etc. to see if they will release their aftermarket designs. I don't see how it would hurt them, and it would build some loyalty with the crowd here for sure. I know Sonnet has gained a lot of respect by still hosting manuals and software on their web site.
 
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if someone could possibly make new upgrade cards, that would be totally sick. i know srmxm or whoever it was made some custom cards with the original G4 PCBs. kinda wish i'd bought one instead of being a price freak, would totally have dual 7455s or 7457s in my QS now
 
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ervus said:
Schematics and PCB layouts are not quite the same thing. If you don't have either they you need to completely reverse engineer an existing design.

You could try contacting Sonnet, OWC, etc. to see if they will release their aftermarket designs. I don't see how it would hurt them, and it would build some loyalty with the crowd here for sure. I know Sonnet has gained a lot of respect by still hosting manuals and software on their web site.
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I did contact Sonnet once with a PPC hardware bug. They were helpful but they have jettisoned all of their PPC stuff. They don't even have a PPC rig in-house to test stuff, nor any of the former staff who knew much about that architecture. I doubt that they would release any old schematics but probably because nobody there knows where they are any more. It won't hurt to ask, though and you should get a reply, even if it is in the negative.
 
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kind of a shame the cards had disappeared without a trace. again, having those layouts would make so much projects easier and even possible. who doesn't want a FAST dual G4 that isn't an MDD?

(...wish i had kept that stupid thing. never knew being MDD-less would be this awful)
 
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If you guys can find pictures of the schematics and pcb layout, I can easily draw it in Altium and upload it here. Who knows, maybe there are some ways to improve the design. :cool:
 
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superlions16 said:
kind of a shame the cards had disappeared without a trace. again, having those layouts would make so much projects easier and even possible. who doesn't want a FAST dual G4 that isn't an MDD?

(...wish i had kept that stupid thing. never knew being MDD-less would be this awful)
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I do, the MDDs are incredibly ugly (only outclassed in sheer fright by the iMac G4) and I already have a Sawtooth.
In other news:
Alright. It made me feel entitled, but I went and sent messages to both Sonnet and OWC regarding it. In ths meantime, I'm not going to give up on my own design, but I will put it on the very backest of burners.
 
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lepidotós said:
the MDDs are incredibly ugly (only outclassed in sheer fright by the iMac G4)
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oh god. yeah i forgot about that but still, they're nice machines... sorta. i would take a G5 any day except mine's broken. some people say the eMac is ugly too (which it kinda is) but it's built so well (again, kinda) that i don't really mind. still have a 2005 eMac running at 1.92ghz.

i wish you the best of luck on your endeavors. having the schematics will make a lot of things possible
 
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Amethyst1 said:
Yeah. They’re just horrible and the 12“ PowerBook really deserved better.
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imagine having software only core image and "DX9" support on windows. not to mention the actual cards saw some bad decisions being made with the pipelining and such. the last 12" should've had 2 memory slots and at LEAST a mobility radeon 9600. for gods sake my eMac blows one out of the water!
 
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Andy from Sonnet got back to ask which board I was asking about in particular. Which is more desirable immediately, a Power Mac upgrade card with L3 or a PowerBook G3 card?
 
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