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View Full Version : G4 class... no true DDR support?


Demon Hunter
Mar 1, 2005, 09:07 PM
It's been said on the boards that the G4 doesn't have true DDR support. What exactly does that mean? If so, what's the point of using DDR memory? Are we really that far behind in the times? Is it all hype/numbers? (the iBook's 266DDR and Powerbook's 333DDR... .00000001% speed improvement?)

:confused:

Sun Baked
Mar 1, 2005, 09:13 PM
The memory controller fully supports DDR memory as does the CPUs L3 cache -- but the FSB of the CPU is SDR and currently saturates at slightly over 1GB/s.

So the CPU really cannot fully use the DDR memory bandwidth that is available (2.1GB/s or 2.7GB/s)

Of course memory is still the biggest hurdle since not enough of it limits you to the 50MB/s of the HD.

Dont Hurt Me
Mar 1, 2005, 09:54 PM
Also G4s DDR for the most part is only half used, G4s are unable to move data on both the up and downs of the clock so they dont really utilize all that ram capability. Apple was able to market DDR though most users had no idea it was only half used. Sure the memory could move data on the ups and downs of the clock but the G4 couldnt. Even with these handicaps old G4 seems to be hanging in there pretty tough when compared to G5. On paper you would think the G5 just tromps G4 where in reality a G5 clock for clock isnt that much faster. Hope that helps.. we have G4s now at G5 speeds. I would like to see a direct comparison of performance. Not the crap Apple spins out.

Love your signature dfarrara, FX5200 is cheap,cheap cheap. not fitting for a Mac at all.

Demon Hunter
Mar 1, 2005, 10:19 PM
Love your signature dfarrara, FX5200 is cheap,cheap cheap. not fitting for a Mac at all.

Haha, right on bro.

Thanks for the insight guys. :)