iMac Dissapointment

[Matt]

According to this, the iMac G5 is only 16% faster than the previous model. Not much of a breakthrough in my eyes.

http://www.lowendmac.com/musings/04/0901.html

 

[Bmode]

You could possibly be looking at the wrong things? There's more than meets the eye!

 

[Matt]

Like What? The case? I hope those benchmarks are wrong though, anyone think this might be a fault?

 

[citystar2k]

according to what apple are saying here, it runs applications a lot more faster than the "16%" quoted.

 

[schweb]

The other thing that everyone needs to realize about the G5 processor is that as a single unit, it's not all that much more powerful than a G4 (except clock speed). The real benefit of a G5 is when it's in a multi-processor configuration.

 

[Avalon]

At least this is true until OS and software will be converted to 100% 64bit applications, because this is a major advantage of the G5.
BTW, this is also true for actual AMD 64bit CPUs... as long as Windows is 32bit, there's not much advantage but the clock speed...

The PowerMacs also have the advantage of the faster system bus, which can make a major difference in overall performance. So the iMac G5 will definitely not be as fast as the single CPU PowerMac G5.
But I'm pretty sure it outperforms any iMac G4, by more than 16% (overall performance, not raw CPU performance).
What really is a big disappointment is the nVidia FX5200 graphics...why did they put the slowest nVidia chip in it?!?

 

[Matt]

I thought the clock speed was the speed of the processor? Whats clockspeed then?

Yeah, the nVidia chip isn't good, you would think Apple would have put a big effort into this, the first average consumer G5.

 

[Avalon]

The clockspeed is a big part in CPU speed, but not all.

Just a little math example:
the smallest entity in the digital world is 1 Bit, right?
So, 8 Bits = 1 Byte
This means, a 32-bit CPU can get 32 Bits (4 Bytes) of information in one cycle (called 1 Hz), while a 64-bit CPU could get twice the size (8 bytes) in the same cycle.
This means a 64-bit CPU like the G5 would outperform a 32-bit like the G4, even at the same clockspeed. But for this, the OS and the application must take completely advantage of those 64-bit.
I know this is an over-simplification, and there are more factors, but it's just to show you that raw clockspeed isn't everything.
Sun's SPARC CPUs are running quite low clockspeeds, compared to actual Intel, AMD or PowerPC, but yet they are very fast. That's why they are still used in powerfull workstations.

It's like the maximum speed of a car doesn't only depend of the horsepower, but a lot more factors (weight, aerodynamics etc).

As OS X actually, and still with Tiger, isn't yet completely a 64-bit OS, and neither are available applications, I expect a noticeable speed bump once it gets there...
I'm pretty sure that if a 100% 64-bit OS (like Sun's OS for example) would be ported on the G5, it's performance would just outperform any actual 32-bit CPU.

 

[PinkPhishDoors]

There is much more than just "clock speed", There is the frontside bus, which in the G4(all models, not just iMac) the FSB sucked, it was like 166 mhz, ir something. On the G5 iMacs it is 600 mhz, and on the Powermacs, it goes up to 1.25... And don't forget it had 3 times more Frames Per Second in both UT 2004, and Halo. Also it is much much much ,much ,much ,much , cheaper than the G4 iMac especially than in context with what you get. Don't forget how much Macs were just 7 years ago, a mac couls cost you over 5000 dollars, apple has come a long way!

 

[Avalon]

The frames-per-second thing doens't say much about a CPU, as it mainly depends of the graphics card. Especially on a Mac, which still isn't the best gaming machine (not even the PM G5), FPS isn't really a good comparison.

Anyway, what's the deal whit that FPS hype? The human eye's reaction being quite slow, it doesn't see a difference between 50 fps and 100 fps... only when you turn on a FPS-counter in your game, you see the value...so who cares?!?

 

[Slammin_SoSo]

Hi Guys,
Can anyone help me here? What is the difference between a G5 1.6 ghz computer and a Pentium 4 2.80ghz or more?

Whats is better a Intel PC or a macintosh imac?

The frames-per-second thing doens't say much about a CPU, as it mainly depends of the graphics card. Especially on a Mac, which still isn't the best gaming machine (not even the PM G5), FPS isn't really a good comparison.

Anyway, what's the deal whit that FPS hype? The human eye's reaction being quite slow, it doesn't see a difference between 50 fps and 100 fps... only when you turn on a FPS-counter in your game, you see the value...so who cares?!?

 

[Avalon]

Hi Guys,
Can anyone help me here? What is the difference between a G5 1.6 ghz computer and a Pentium 4 2.80ghz or more?

Whats is better a Intel PC or a macintosh imac?

Search the forum...there have been an excessive amount of threads and posts about this...an eternally unanswered question...
What's better for you depends on what you want, and what you want to do, there is no general answer to this.

And BTW, it's called Apple iMac, not Macintosh iMac

 

[MoltenLava]

The other thing that everyone needs to realize about the G5 processor is that as a single unit, it's not all that much more powerful than a G4 (except clock speed). The real benefit of a G5 is when it's in a multi-processor configuration.

Please elaborate for everyone why the real benefit of G5 is when it's in a multi processor config.

 

[MoltenLava]

Ok, here's the deal with "MHz myth". Read carefully, as I won't repeat twice.

The CPU clock in MHz is an indication of how fast the CPU can move, so to speak. MHz is usually a very good indicator of speed _only_for_the_same_CPU_family_. Again, only for the same CPU family. G3/G4/G5 are in the same family. CPU clock among those processors are a good indicator of relative speed. Same goes for Intel P2/P3/P4. I said "usually", because even in the same family, the performance can be improved drastically by the use of more pipelining, branch prediction, superscalar, etc, which is not the scope of this article.

The CPU clock is a VERY poor indicator of performance across different processor family. 1GHz G5 and 2GHz P4 can't be compared with just clock rate. The reason for that is the "work" that each processor can do per clock cycle is different. I said earlier that the clock rate is how fast the processor can move. Guess what, each processor have different "efficiency", so to speak. For example, to perform a simple arithmetic multiply may take one processor 1 clock cycle, while another processor 10 clock cycles. Yet the third processor may perform addition and muptiply in one clock cycle! That's why you can't just compare MHz vs MHz, because the work that the processors can perform in each MHz are different.

32bit vs 64bit processor, IMHO, is a big marketing hype. 64bit processors are not twice faster than 32bit processors as they might (wrongly) imply. The advantage of 64bit processor is what Avalon has explained. In order to add two 64bit numbers, it takes one clock cycle for 64bit processor, while it takes several (not just two) clock cycles for 32bit processors. But then, we don't generally deal with 64bit numbers. The maximum addressable number in 32bit space is 2 (or 4) billions. That's certainly big enough for me, although certain applications may need larger address space.

Having said all these, I'm not surprised to find 16% increase or whatever with iMac G5. Look at their benchmark. One is completely disk IO bound, which has very little to do with processing power, and the other two are completely CPU bound. They are not "good" benchmarks because they are biased towards certain subsystem, rather than measuring overall system performance.

 

[Avalon]

Wow, that IS a really good explanation...couldn't say it better