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I was just wondering if there is a web site with a description of the different G4 processors used in Macs, their caracteristics, speed, etc. I've found a Motorola site but it includes processors not in Macs and It doesn't really help.

I'm thinking of bying an E-mac but wonder if the "budget" version of the G4 in there is much slower than the G4 in the Powerbooks and the Towers.

Thanks for any info.

Marc P.
 

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In general, all G4s perform pretty well the same. What you want to watch is how much L3 cache and the bus speed the machine has. L3 cache usually provides a nice boost in performance. Some machines have no L3 cache which makes them perform slower than a similar machine with L3 cache. You'd probably only want to look at bus speed if your considering an older machine, the newer machines I believe are all above 100Mhz in bus speed and the difference between 100, 133, and 167 is probably not too noticeable.

I don't really think there are "budget" G4s by the way, I think there's just a difference in the power usage, some are low wattage versions for iMacs, Powerbooks and iBooks. The G3 is more of a budget G4.
 

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That's incorrect - the chip type and caching make a big difference - a single 533 7400 chip with a 1 meg L2 cache easily beats a 733 7450 with 256 L2.
Work per clock cycle, cache size, bus speed all have a part to play. 100 mHz bus speed eMacs and iMacs are not very powerful with their 256L2 cache despite 700 and 800 clock speeds. Figure they are equivalent to 400-500 earlier processors with large L2 caches.
When you get to 867s with 2 meg L3 and 933s and up then you get significant performance gains.
A single 867 with the 2 meg cache comes pretty close to a dual 800 in performance :eek:



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<BLOCKQUOTE>quote:</font><HR>Originally posted by macdoc:

A single 867 with the 2 meg cache comes pretty close to a dual 800 in performance
<HR></BLOCKQUOTE>

Yeah, right. I don't think so. In tests where the DP800 is using a single processor, maybe, but in any SMP tasks, the DP800 trounces the single 867.
 

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Bus Speed is probably equal to L3 cache in terms of perfomance/importance.

In tests (such as this one*, which is as close to a real world test as I have seen). the DDR DP1000 (1MB L3/167 Bus) beats the SDR DP1000 (2MB L3/133 Bus).

There are a lot of factors to consider, so be sure to consider all of them.

--PB

* The linked test does not take advantage of Altivec or Dual processors, but considering the wide range of machines involved, I'd still say it was one of the more acurate, real world tests I;ve seen.
 
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