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View Full Version : Future G3 vs G4


macphoria
Jan 1, 2003, 07:33 PM
I read rumor news suggesting newer faster versions of G3 might show up in Apple products, most likely iBook. And from what I have read, G3 was not designed to handle multi-tasking whereas G4 was. I think this is very important difference because since I've gone from OS 9 to OS X, the advantage in multi-tasking (web surfing while rendering a movie, watching dvd while doing photoshop etc) is making it virtually impossible for me to even going back to OS 9 even though most of my software library still is OS 9 based.

I recently tested this on iBook 700mhz and its performance was rather disappointing. From my observation, PowerMac G4 533mhz (single processor) still performed better.

So my question is,
1) will future G3's with higher clock speed handle multi-tasking better? Can raw speed overcome multi-tasking obstacle? Or is this a hurdle G3 can't overcome because of its design?
2) I read that G4 is essentially G3 with Velocity Engine built in. But because VelocityEngine G4 is from Motorola and current G3 line is from IBM, it is unlikely that G3 line will not be upgraded with VelocityEngine-like feature. Is that the case? I hear IBM Power4 based chip which will likely become G5 has it's own version of VelocityEngine. Is this something that could be implemented on G3?

bousozoku
Jan 1, 2003, 10:41 PM
IBM has used versions of the G3 in multiprocessing configurations in the RS/6000 line and is working on a permanent solution that could be used on Macs. As far as multi-tasking goes, there's no difference in the processors. Mac OS X uses AltiVec (a.k.a. Velocity Engine) to advantage to make things faster. A faster hard drive/hard drive interface will help as well.

IBM has a licence to AltiVec and has apparently used it for embedded applications such as networking (routers, bridges, etc.) It can be added to any G3 design but it takes a lot of space. Had they designed the G4 without AltiVec, its floating point performance would have been much better and more applications would have benefitted than do now from AltiVec.

ddtlm
Jan 1, 2003, 11:46 PM
bousozoku:

Had they designed the G4 without AltiVec, its floating point performance would have been much better
So you assume that Moto would have provided better floating point units if they did not have AltiVec? I do not agree... this would have meant that the primary difference between G3's and G4's would be in floating point math, which does not at all mirror reality. Remember that AltiVec's integer prowess is responsible for the power of G4's in RC5, and it is (edjucated guess) AltiVec's integer abilities that make it useful in networking equiptment. A fair amount of Photoshopping is probably integer-based as well.

It's interesting that everyone equates the G4 with floating-point power when in fact it is by far biased towards integer speed in both scalar and vector units.

lmalave
Jan 2, 2003, 11:58 AM
Originally posted by macphoria
I read rumor news suggesting newer faster versions of G3 might show up in Apple products, most likely iBook. And from what I have read, G3 was not designed to handle multi-tasking whereas G4 was. I think this is very important difference because since I've gone from OS 9 to OS X, the advantage in multi-tasking (web surfing while rendering a movie, watching dvd while doing photoshop etc) is making it virtually impossible for me to even going back to OS 9 even though most of my software library still is OS 9 based.

I recently tested this on iBook 700mhz and its performance was rather disappointing. From my observation, PowerMac G4 533mhz (single processor) still performed better.

So my question is,
1) will future G3's with higher clock speed handle multi-tasking better? Can raw speed overcome multi-tasking obstacle? Or is this a hurdle G3 can't overcome because of its design?
2) I read that G4 is essentially G3 with Velocity Engine built in. But because VelocityEngine G4 is from Motorola and current G3 line is from IBM, it is unlikely that G3 line will not be upgraded with VelocityEngine-like feature. Is that the case? I hear IBM Power4 based chip which will likely become G5 has it's own version of VelocityEngine. Is this something that could be implemented on G3?

Well, I don't know about future IBM G3's, but the IBM 970 definitely has Altivec. I don't know how much longer IBM is going to develop the G3, though. The latest buzz is Moto's new 7457 G4, which goes from 1 GHz to 1.4 GHz and only consumes 7.5W of energy vs. 12W or so for the current G4. So it's looking increasingly likely that Apple will just move to the G4 for the iBook, retiring the G3 from the Apple line (not sure what they'll do with the CRT iMac, but if they keep it at all it will also probably get the lowest-MHz G4). Too bad - the G3 is a great chip - I really like the one in my iBook.

brandon6684
Jan 2, 2003, 03:05 PM
Originally posted by macphoria
And from what I have read, G3 was not designed to handle multi-tasking whereas G4 was.

286 and 68k processors can handle multitasking, although there aren't many operating systems fir those arcitectures. It's the operating systems that does the multitasking.