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The Battle in 64-bit Land, 2003 and Beyond
An anonymous reader writes "Paul DeMone has an excellent article up at Real World Technologies on the future of 64bit computing. Find out where MIPS, HP, Intel, AMD, Sun, Fujitsu, and IBM are headed."
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The article is very detailed on many points, but doesn't seem to have much mention of environmental aspects like heat dissipation. I can remember when this was a big issue with every new CPU, but lately it seems to have been swept under the rug. What's changed?
I'm certainly interested in the speed of CPUs, but heat production in the embedded space happens to be a bigger issue for me.
Could I interest anyone in some toast?
Lousy I/O?
A few weeks ago, I was looking into buying a $35,000 Sun system. I needed a machine with better memory bandwidth than a PC could offer. The machine in question interleaved its memory 8 ways, if you had all of the processers!
Then, I noticed that each bank ran at 75 MHz. Boy, was I shocked. That means that all 8 banks together run at the equivalent of 600 MHz. The new Granite Bay chipsets, with dual DDR 333, give you the equivalent of 666 MHz.
Both systems use PCI to connect to the outside world. The PC has a 533 MHz front-side bus, and an AGP port. I can't think of anywhere that the Sun would have had any better I/O.
Now, when you get into 8-way systems, the I/O between processers is better on the "high end" machines. But before you can come up with more I/O than a modern PC, you have to spend about 6 figures. In other words, two ORDERS OF MAGNITUDE HIGHER!
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
In and of itself, a 64 bit processor with a 64 bit operation system really doesn't mean better performance. You've really got to have application which leverage that kind of platform. And there aren't many. On my SPARC servers (which all have 64 bit CPUs), going from a 32 bit OS to a 64 bit OS so no real improvement or degradation regarding performance in a wide variety of applications. Going 64 bits for most people mean nothing.
The main selling point for SPARC, which most people who aren't dealing with Sun don't understand, is not the CPU itself or the speed of a uniprocessor box.
It is the total package. (Admittedly, the lower part of that is the uniprocessor performance.) On the upside, Sun has some very compelling benefits. Almost all major UNIX programs (commercial) are developed for SPARC, often as the primary development platform. The binary compatibility is awesome. The binary tat I compiled on my workstation (with 5 years old technology that is several CPU generation behind) will containue to run the most modern hardware. There's no recompiling for different/newer architectures (unless you're looking to gain a specific advantage of a new processor and your compiler can do it). And probably one of the best features is an awesome scalability story. If your code does threads, or uses more than a processor at a time, you can scale from a 1 CPU to 100+ CPU configuration. No special programming to worry about clusters or to take advantage of new hardware. Additionally, because the hardware is (majority) single vendor, you gain a great deal of relaibility over platforms which has an incredible amount of diversity (wintel). Okay. That's a double edge sword, admittedly.
That said, it is too bad that Sun just can't keep up in the uniprocessor world. But it has quite a number of real-world advantages beyond performance which keep it afloat, which may surprise people.
The instruction set and register layout is irrelevant. All modern X86 CPUs translate the inctruction stream on-the-fly to an internal RISC-like architecture with multiple parallel execution units. Using register renaming, all modern X86 CPUs have dozens of general-purpose physical registers that can be simultaneously mapped onto the legacy logical registers.
There is no need to expose the internals of any particular CPU generation to the software because the details change with each new design. The CPU's on-the-fly recoding knows how to optimize for the details of its particular internal implementation better than a C compiler. (Exposing the implementation details to the compiler is one reason why I think that the whole Itanium concept is a bad idea in the long run.)
The floating point performance is a function of the target market. If a CPU manufacturer was so inclined, they could create an X86 with world-record FPU performance. It's just not needed for the majority of places where X86's get used today.
Actually, the IA64 performance is very bad in the real world. True, their benchmarks look impressive, but I haven't been able to reproduce that.
;)
I had the opportunity to log in to an 4-way 900 MHz itanic-2 box, which was outperformed by my lowly 900 MHz Pentium 3 notebook by a factor of 4 (single CPU benchmark). I did some mp3 en- and decoding and compiling on the box.
Also, ia64 is spectectularly bad for MPEG-4. Go ask google for ia64 and xvid and you will find a computer science class in Germany trying to optimize ia64 and they found that after their optimizations (which yielded a big speed-up) ia64 still was handily outperformed by their el-cheapo desktop Athlons.
Take those benchmarks with a grain of salt. I basically think that IA64 is a big flop. Intel needs a miracle to make people buy this crap. But, as they say, your mileage may vary.
It is such a shame to see good CPU architechtures die, and crap live on.
The Motorola 68K family were a joy to work with - lots of registers, and a very orthoginal instruction set - you could use any A register for pointers, any D register for data - none of this "ECX is for loops, EDI for destination pointer, ESI for source pointer" crap of the x86.
It's dead now, save for use as a microcontroller.
The Alpha was a ass-kicking, name-taking monster. While I never seriously programmed on it, it was 64 bits long before anybody else knew how to spell it - it had well established software and compiler technology. It is STILL one of the leaders.
But for all intents and purposes, it's dead, Jim. Yet Itanic, with an unproven design concept, is flourishing (sorry, having worked with DSPs that implemented the VLIW idea, I have doubts about the real-world performance of VLIW in a multitasking environment).
As Billy Joel said, "Only the good die young...."
www.eFax.com are spammers
Unfortunately, none of the current crop of 64 bit processors deliver: the cost of true 64 bit systems (those capable of actually using more than 4 Gbytes of memory) generally starts somewhere upwards of $10000, and for that you do not get anywhere near 10 times the performance of a $1000 PC.
The main reason right now to get a 64 bit system at current prices is because the applications just cannot be shoehorned into a mere 2-4 Gbytes. If AMD can change that equation and deliver comparable bang-for-the-buck to current PCs, with 64 bit addressing being icing on the cake, they have a winner. None of the other players seem to be capable of doing that--they have tried and failed miserably so far.