Registered ECC SDRam in G3/G4 ?

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Registered ECC SDRam in G3/G4 ?

Postby Renegade » 01 Jan 2012, 12:26

Hello and Happy New Year to you guys !

Just wondering: do B&W G3s and pre-MDD G4s accept ECC Registered memory modules ?
I know that standard and registerd ram should'nt be mixed, but what if the G3/G4 ram banks are populated only with registered ecc ?

Cheers.
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Re: Registered ECC SDRam in G3/G4 ?

Postby Byrd » 01 Jan 2012, 23:14

I'm fairly sure ECC registered/buffered RAM won't work in any Mac bar Xserves
:: Current project Mac: PB1400 resto
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Re: Registered ECC SDRam in G3/G4 ?

Postby Rodus » 05 Jan 2012, 21:10

I have one ECC stick that works fine in my G3 400 iMac and my Sawtooth.
27" iMac i5, Dual G4 Sawtooth, 1.42 eMac, iMac G3, iBook G3, Pismo, B&W G3, Beige G3, PM 9500 + Sonnet G3, Performa 6400 x 2, Performa 5200, LC475, IIvi, PB 100, Newton MP 2000 - WiFI & Bluetooth, iPhone 3G, iPhone 4S, iPad
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Re: Registered ECC SDRam in G3/G4 ?

Postby Gorgonops » 05 Jan 2012, 22:36

*Unregistered* ECC RAM might work in a G3/G4. Apple systems in general are "picky" about DIMMs (I've had really bad luck trying to use apparently perfectly good RAM pulled from Pentium IIIs and Athlon machines in my B&W G3) but the only difference between unregistered ECC and non-ECC DIMMs is the ECC DIMMs include an extra 8 data bits which the host system is free not to use. So if the system is otherwise OK with the specs and configuration EEPROM data of an ECC stick there's no reason a Mac won't work with it.

"Registered" RAM on the other hand actually has a buffer sitting on some of the control lines, and since its presence induces additional latency (while improving reliability) the memory controller actively needs to compensate for it. So far as I know no Macs which uses SDRAM supports it. I could be wrong, but I'm fairly sure that's the case.
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