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Baby_Hitler
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Are Mac MHZ > PC MHZ?
#4463353 - 07/28/05 03:21 AM (18 years, 8 months ago) |
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I'm speaking specifically of laptops/notebooks.
I'm looking for one that's the equivalent in processing power to a 300 MHZ PC laptop. Seems like I was told that Macs get more power from fewer MHZ, but I'm not sure if that is just for regular computers, or if it's true for portables as well.
I'm buying this for wardriving, BTW. What should I look for?
-------------------- "America: Fuck yeah!" -- Alexthegreat “Nothing can now be believed which is seen in a newspaper. Truth itself becomes suspicious by being put into that polluted vehicle. The real extent of this state of misinformation is known only to those who are in situations to confront facts within their knowledge with the lies of the day.” -- Thomas Jefferson The greatest sin of mankind is ignorance. The press takes [Trump] literally, but not seriously; his supporters take him seriously, but not literally. --Salena Zeto (9/23/16)
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Seuss
Error: divide byzero
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Re: Are Mac MHZ > PC MHZ? [Re: Baby_Hitler]
#4463429 - 07/28/05 04:47 AM (18 years, 8 months ago) |
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For a simple question, the answer is very complex. The Hz of a CPU is meaningless... it is a marketing gimick started by Intel to get people to upgrade to "faster" chips. What really matters is called CPI (cycles per instruction) which is a measure of the number of clock cycles it takes to execute a single instruction. One CPU might take 100 clock cycles to do a multiplication, while another chip might only take 10 clock cycles. If both chips are clocked at 1GHz, then the chip that only takes 10 clock cycles to multiply numbers will multiply numbers 10 times faster even though both chips "run at the same speed".
The 80x86 (pentium, pentium pro, pentium 4, etc) are called CISC chips. A CISC chip uses a Complex Instruction Set. The language that the CPU understands is complex. What this means is that a single instruction can do a whole lot... perhaps move a word of data from memory into a register and increase the value in another register... all with a single instruction. The advantage of a CISC chip is that it is very easy to write assembly by hand... a single instruction does a lot. Another advantage is that binaries (and memory footprints) are small... one instruction does a lot. The disadvantage of a CISC chip is that it takes lots of clock cycles to do a single instruction... becuase a single instruction is complex. It is also much harder for a compiler to optimize the code for a CISC chip.
An Apple computer uses a PowerPC chip, which is a RISC chip. A RISC chip has a Reduced Instruction Set. The goal of a RISC chip is to execute every single instruction in a single clock cycle. To make this work, the designers only implement very simple instructions. It is up to the programmer to combine the simple instructions to do the equiv of a complex instruction on a CISC chip. The advantages of this are great. The chips are much simpler to create and all of the extra die space can be used to optimize the speed of the chip. Because there are so many more instructions in the code, the compiler can really optimize the code. The disadvantages are there as well... the memory footprint is bigger because it takes more instructions to do the same thing. It is also much more difficult to write assmebly by hand.
(Although intel provides an external complex instruction set, they implement a risc core and translate the complex instructions into a series of simple instructions within the chip to try and gain some of the benefits of the risc design.)
If you understood the above, you see why it becomes very difficult to compare the performance of two CPUs. To really get a good metric, you would need to take an actual program and calculate out the average CPI for the execution path of the program on both the CISC and RISC verions of the binary. Once you have the average CPI for both, you can use it to normalize the clock speed of each CPU and calculate the true throughput of the CPU for the application used. A good metric would compare several different types of applications, integer intensive, floating intensive, bus intensive, etc and average out the results.
In my experience, typically, the PowerPC (in the Apple) outperforms the Intel chips when identical clock rates are used. There are too many factors to say this is always the case, but on average, I would say it is true.
-------------------- Just another spore in the wind.
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trendal
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Re: Are Mac MHZ > PC MHZ? [Re: Baby_Hitler]
#4463583 - 07/28/05 06:07 AM (18 years, 8 months ago) |
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The simple answer is: yes.
Generally a Mac of comparible power to a PC will have a much lower clock speed.
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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Krishna
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Re: Are Mac MHZ > PC MHZ? [Re: Seuss]
#4463628 - 07/28/05 06:58 AM (18 years, 8 months ago) |
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isn't apple switching to intel, though? will they keep RISC architecture, or will they switch over to CISC?
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trendal
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Re: Are Mac MHZ > PC MHZ? [Re: Krishna]
#4463667 - 07/28/05 07:29 AM (18 years, 8 months ago) |
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I expect they'll stick with the RISC architecture.
Switching over to CISC would be a huge change, and would require porting way too much Mac software over to the CISC architecture.
They'll just get Intel to build their PowerPC chips (or something similar) instead of IBM.
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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delta9
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Re: Are Mac MHZ > PC MHZ? [Re: trendal]
#4463677 - 07/28/05 07:38 AM (18 years, 8 months ago) |
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Quote:
trendal said: I expect they'll stick with the RISC architecture.
Switching over to CISC would be a huge change, and would require porting way too much Mac software over to the CISC architecture.
They'll just get Intel to build their PowerPC chips (or something similar) instead of IBM.
What are you on about? I am of the understanding Mac software is written with portability in mind now that they have their fancy unix back end. Really, I don't see why if I can run debian linux on intel CISC and power pc RISC chips because the C and C++ compilers make the final decisions, it should be all that much more different for compiling Mac's code.
-------------------- delta9
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trendal
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Re: Are Mac MHZ > PC MHZ? [Re: delta9]
#4463706 - 07/28/05 08:09 AM (18 years, 8 months ago) |
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There are some important hardware differences between the Mac and PC architecture beyond just the CPU instruction set.
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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delta9
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Re: Are Mac MHZ > PC MHZ? [Re: trendal]
#4463742 - 07/28/05 08:34 AM (18 years, 8 months ago) |
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Understandable, but why is it less troublesome to go from PC to Mac architecture than vice versa? I don't think it is.
-------------------- delta9
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trendal
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Re: Are Mac MHZ > PC MHZ? [Re: delta9]
#4463757 - 07/28/05 08:43 AM (18 years, 8 months ago) |
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I never said it was...
I'm under the impression that it's rather difficult to go from PC -> Mac.
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Once, men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.
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Seuss
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Re: Are Mac MHZ > PC MHZ? [Re: delta9]
#4463761 - 07/28/05 08:45 AM (18 years, 8 months ago) |
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With OS-X and the new Apple tools it is possible to create applications that will run on both PowerPC and Intel chips. I can compile once and the binary will run under both architectures. Pretty impressive... real innovation (as compared to the BS microsoft spouts).
See: http://developer.apple.com/documentation/MacOSX/Conceptual/universal_binary/ for details.
> why is it less troublesome to go from PC to Mac architecture than vice versa?
Because OS-X is easier to use than windows. (I am not claiming that one is better than the other, only easier to use. No OS wars, please.)
-------------------- Just another spore in the wind.
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delta9
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Re: Are Mac MHZ > PC MHZ? [Re: Seuss]
#4463787 - 07/28/05 08:59 AM (18 years, 7 months ago) |
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Quote:
Seuss said: > why is it less troublesome to go from PC to Mac architecture than vice versa?
Because OS-X is easier to use than windows. (I am not claiming that one is better than the other, only easier to use. No OS wars, please.)
You misinterpret me. We are talking about migrating software across architectures... Like how Debian is available on PowerPC *and* x86 architectures. We were talking about that because someone asked whether or not Mac might go to a CISC processor, and trendal stated it would be too difficult to port. Being a debian elitist and knowing that current macs run unix, I found this to be improbable.
-------------------- delta9
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Baby_Hitler
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Re: Are Mac MHZ > PC MHZ? [Re: Seuss]
#4463815 - 07/28/05 09:07 AM (18 years, 7 months ago) |
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Yeah, I have had a PC computer for years. I'm just in the market for a portable computer, and have decided to go Mac just, you know, to try something different.
It also seems like old Mac laptops are cheaper than old PC laptops (a.k.a. "IBM Clones") of even the same clock speed.
-------------------- "America: Fuck yeah!" -- Alexthegreat “Nothing can now be believed which is seen in a newspaper. Truth itself becomes suspicious by being put into that polluted vehicle. The real extent of this state of misinformation is known only to those who are in situations to confront facts within their knowledge with the lies of the day.” -- Thomas Jefferson The greatest sin of mankind is ignorance. The press takes [Trump] literally, but not seriously; his supporters take him seriously, but not literally. --Salena Zeto (9/23/16)
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