One other argument for a G3 upgrade is, if the machine is needed for something serious, that third-party daughter cards circumvent the designed-in throttling of the 1400 to 32-bit transfers by having their own inbuilt 64-bit data paths.
de
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(60x) 13DT + 3PB + PTPro; (G3) 7DT/MT; (G4) 3T + PB. System 8.1 to OS 10.5.8
de
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(60x) 13DT + 3PB + PTPro; (G3) 7DT/MT; (G4) 3T + PB. System 8.1 to OS 10.5.8