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What Makes Apple's Power Mac G5 Processor So Hot
An anonymous reader writes "58 million transistors can drive a lot of power. Apparently, Apple appreciated the choices IBM processor architects made when designing the 970 family. This article provides the 64-bit architecture big picture for the 970 family (A.K.A. the Power Mac G5) and the critical issues in IBM's 64-bit POWER designs, covering 32-bit compatibility, power management, and processor bus design."
Basically, we took one of our superchips that go into superservers, with a gitastic cache and frontside bus, stripped it down a bit so we don't cut into our own market, and gave it a new name. Isn't that cool?
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I was able to hold my hand on the heatsink and it was barely warm.
It could be because there's inadequate conduction between the CPU core and the heatsink. Check the temperature monitors to make sure it's actually as cool as you hope it to be. It could be that just most of the heat is staying in on the CPU, which would be a bad thing. Hopefully you've already checked this though.
Capable of addressing an astronomical 18 billion GB, or 18 exabytes, of memory,
I know the first 2 digits are 1 and 8, but 2^64 bytes is still 'only' 16 exabytes...
In most meaningful, sizeable programs, pointers aren't a significant chunk of memory usage. (And for small programs, it doesn't matter.) I would think most modern apps consume most of their memory storing images, which aren't affected by the 32->64 change.
Also, 64-bit pointers allow you to go from a max of 4GB of RAM to 16 billion GB, so the assumption is memory prices will keep dropping and you'll have much more than twice as much RAM on your 64-bit system anyway.
Ooh, a sarcasm detector. Oh, that's a real useful invention.
umm, what heat problem? the 9 fans and liquid cooling are in their respective models to solve a SOUND problem. not a heat problem. but then if you bothered looking up statistics on the G5 you would not be able to bash the mac would you?
I am the Alpha and the Omega-3
Since the AMD64 instruction set can also run code compiled for 32 bit, it can also work with 32 bit pointers. However, any code optimized for AMD64, will probably contain all 64 bit pointers.
I guess if you plan on shelving out for 64 bit, you should plan on getting more ram w/ it.
The *BIG* thing for x86 for "64bit computing" is not in fact the 64 bitness but doubling the number of GPR!
As the PPC instruction set is sane (x86 is not, urgh), beside the extra-instruction needed for 64 bit computing, there are very few difference between a PPC running on 64bit code or a PPC running on 32bit unless of course you have an app which needs more than 4GB of memory or do lots of 64-bit integer calculation..
I can buy .8-1.2ghz processors and motherboards that use extremely little power (tens of watts running full bore) and are certianly very useable with even windows XP running on it as a internet/ general use home or office pc.
But for some reason most people believe they need a 6.8ghz 2.2terabytes of ram and 15,000 rpm hard drives along with a hairdryer add on known as a 3d video card, bringing that machine up to the 400 watts+ power consumption mark.
and where does most of that energy go?? that 's right . HEAT.
Switch to mini-itx computer with a low-power processor, laptop hard drive and flat panel monitor, and you will generate very little heat, use 1/20th the electricity your current space heater under your desk called a comouter does and still get the same general computing done with the same speedy feel.
will you increase your lead in the seti@home, doom3, other CPU intensive tasks? nope. but office 2003, WinXP and all other office apps as well as most non 3d intensive games run perfecly.
Do not look at laser with remaining good eye.
So in your 64bit OS, with your 64 bit application you run into overflow errors in years to come.
We recently ran into a serious undiscovered bug in the original core of our application.
Some wise ass developer thought that a 16bit integer would be enough for storing the index.
All was fine for years and years until the first person had >16383 individual transactions in a job.
Whilst you can't do anything about true future proofing, you can think about handling 64bits now, and making sure your application can expand flawlessly into that realm should be considered.
It does also involve thinking logically, there is no point in using absolute memory references in a small array, but for expandable dictionaries and trees, its better to code in simple chunks.
Just because you can't afford it doesn't mean it's a bad computer (doesn't mean it's a good computer either).
Hear hear.
I've priced out equivalent machines to the current Apple offerings, and you do indeed get what you pay for. A dual-CPU 1.8Ghz Powermac is around $2500 sans monitor. Price out a dual-Xeon or dual-Opteron and you end up at around $2000-$2500 for a comparable system.
Where Apple might be missing the boat is in the ultra low end where you can buy a system for $600. (But why should they try to compete down there where margins are razor-thin?)
Wolde you bothe eate your cake, and have your cake?
The quest for CPU power has been largely defeated by bloated software in applications and operating systems. Some programs I wrote in Basic on an Apple II ran faster than when written in a modern language on a G4 Dual-processor Mac with hardware 1,000 times faster.
Come on. What language are we talking about here? My basement collection includes a II+, a IIe, two IIcs and a Franklin compatible. I challenge anyone to come up with a program in Applesoft that runs faster on one of my museum pieces than on a modern Mac using C++, Java or even Perl. I mod his article -1 for troll.
While software has become bloated and to some extent inefficient, people often forget that we expect a lot more from our computers now than the single-tasking 80 column display days.
My cat can eat a whole watermelon
I agree, big time.
I used to be very pleased that my Macs lacked a CPU fan while x86 users where bolting on everything but the kitchen sink in efforts to cool their systems down.
More important, Macs had just one fan -- the power supply fan -- to cool the entire box while x86 systems were fucking festooned with them.
Nowadays, though, a prudent Mac owner should at least consider his home air-conditioning system's cooling capacity since G4's and G5's will definitely heat up a room.
And I don't even want to get into fan counts.
I'd like Apple to make a nice, fast, cool, quiet system... and here's how to do it: underclock.
Modern CPU's are grotesquely overpowered for the needs of 99.9% of the general public. Crank those babies back.
The fruit of research and progress are not merely systems that can run faster and hotter, but faster and cooler... quieter.
Never going happen while there's this pissing contest going on, though.
--Richard
If you don't need that kind of power, you should stay on the lower end. The G5 iMac or the eMac don't seem to run all that hot.
As for fan count, presumably you're referring to the PowerMac G5. Apple preferred more low-speed fans over a few high-speed fans as a noise reduction measure. What was your complaint?
Where Apple might be missing the boat is in the ultra low end where you can buy a system for $600. (But why should they try to compete down there where margins are razor-thin?)
Because poor college students like me, who buy $600 computers is going to buy a PC. And when I get out of college and have the means to drop $2500 on a computer, guess what I'll probably buy.
Actually, the two real reasons why Apple doesn't sell low end machines is that it would undercut sales of their more expensive machines, and totally destroy the second hand Mac market (where used Macs are way overvalued, IMHO). Without a strong second hand market to sell a used Mac for a good price, people will be less likely to buy their high end machines.
But that's why people buy macs. To use photoshop quickly. So how long a filter application takes is very relevant.
:)
I don't have a mac here, but opterons and g5s are probably similar. Pick the one you like, they're both expensive
My other car is first.