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erikm100
2005-03-17, 18:04
Hey, im a student and I was thinkin bout buying a mac. I just have one question what is the difference between a g4 and a g5 besides the speed??

NaMo4184
2005-03-17, 18:32
The 2 processors basicaly aren't even in the same class
Here is a short list

G5 is 64 bit vs G4 32 bit

G5 has the fastest Fsbs.. period. G4 is the slowest fsbs... period.

G5 has a more complicated implementation of altevic. (this is what allows for vector operations)

G5 is H-O-T-T hot while G4s can run fanless given the right condition.

G5 is a server class processor. you compare then to xenon and opteraions and what have you

I think G5 has more L1 and L2 cache

If you want to learn more about the processors go to good'ol apple.com

basically most people don't need G5s

Luca
2005-03-17, 18:44
There's more to it than that. The G5 isn't better than the G4 in every way. For example, the G4 has fewer than half as many pipeline stages as the G5, which makes it a lot faster in certain tasks. And actually, it's a major error to say that the G5 has a more complicated implementation of AltiVec. That's not true at all. The G5's AltiVec code is based on the older, 7400-series G4, which came out in 1999. The current G4's AltiVec code is newer, as part of the 7450-series G4. It's much, much faster than the G5's AltiVec. According to XBench (which isn't a perfectly accurate measure to say the least), a 1.3 GHz G4 beats a dual 2.0 GHz G5 in the AltiVec test. Of course, the G5 can make up for that with its huge clock speed advantage, but it's not always better.

By the way, 64 bit vs. 32 bit makes very little difference for the time being. All it means is that a G4, with 32 bit memory addressing, can only see up to 4 GB of memory. The G5 can see far more (16 exabytes actually, or 16 billion gigabytes). From a practical standpoint, it means you can use as much RAM as you want in a G5. You can put up to 8 GB in a PowerMac G5 at the moment, and in the near future you should be able to put 16 GB or more in. If an application is written to take advantage of 64 bit code, that means you can use more than 4 GB in that application. So if you want to work on a huge video file, you can put more of it into RAM, and thus work faster.

In the end I have to agree with NaMo that most people don't need G5s. If you're just checking email, doing iPhoto, listening to music, and stuff like that, a G4 is fine.

Brad
2005-03-17, 18:50
Also, this fits better in the Purchasing Advice forum. Moving now...

macgeek2004
2005-03-17, 20:09
Why was LUCA banned?

Luca
2005-03-17, 20:17
Why was LUCA banned?
For criticizing Apple, stupid!

:p:p:p:p:p

Brad
2005-03-17, 20:23
Why was LUCA banned?
Let's think about that for a second... :)

http://www.project-think.com/images-3/luca-banned.png

SonOfSylvanus
2005-03-17, 20:26
There's more to it than that...

When will people learn?

Never, ever reply to a mac tech/history post before Luca ;)