AMD's 64-Bit Chip

EyesWideOpen writes "AMD is set to release a 64-bit chip early next year which will be completely backwards compatible with the Athlon line. The current 64-bit offering from Intel, Itanium, is an entirely new chip that has no backwards compatibility with its x86 line of chips (from the 8080 chip to the Pentium IV) and is designed only for high end servers. AMD's solution to this problem is the Opteron chip (product info) which will be in servers, desktops and laptops. Here is a wired article."

Comments

Since when is the 8080...

[ncc74656]

...considered part of the x86 family? The first processor in that lineup is the 8086. I think the 8086 might've been source-code-compatible (to some extent) with the 8080, but you can't take an 8080 binary and run it on any x86 processor (emulation doesn't count).

Re:AMD Reigns Supreme

[(H)elix1]

I found my Dual AMD box to be as good, if not better from a never going down standpoint. Same goes for my gaming boxes. After building a bunch of systems, however, I do have one major beef with AMD...

For the love of god, put a coat of nickel or something on the CPU!

I chipped a couple when rev 1 of the Chrome Orb came out. Fool me once ... Things are a little better these days because the quality heat sinks - with paranoid mode on - are less likely to crush a CPU than when folks were trying to strap a socket 370 heat sink on an Athlon, but I still feel like it is a crap shoot every time I have to remove the CPU. I end up trying to stay about the $100 mark for CPU's as a result. (Yes, the MP's cost me much more, and I was very nervous when I mounted them)

Re:Alpha anyone?

[nadador]

>> very advanced VLIW-esque architecture

Ah, yes. EPIC. Explicitly Parallel Instruction Computing. AKA VLIW. EPIC is market-speak. Intel didn't want to admit that it was making a VLIW chip for two reasons:

1. There is only one company that has every sold a VLIW chip that actually worked, and that people bought: TI makes DSPs, where are VLIW. They make tons of money. They are the only ones that ever did it right.

2. There is only one company that has ever made a good VLIW compiler: TI, again.

Lets think briefly about how great EPIC is, using the two main selling points I remember from a presentation I saw on it a few years ago (sorry if my memory is bad, no coffee this morning, I'm not responsible).

1. Instructions are Explicitly Parallel. So, the compiler tells you that these two or four or however many instructions can be executed without worrying about data dependency. Terrific. Assuming that the compiler actually works, which is still an open question.

The only difference between this setup and what's in your Athlon or Pentium4 is that the looking-for-independence is done in hardware on your Athlon instead of by the compiler on your Itanium. This means that there is the *possibility* that EPIC does better at finding independence because the compiler *should* know more about the code when its in a higher level language. *Should*. Essentially, until the science of compilers takes a quantum leap or we start using programming languages that makes these things easier (correct me if I'm wrong, please), Itanium will be at most as fast as a superscalar processor that finds independent instructions on its own and does register renaming.

2. Predicates and conditional execution. While the whole notion of the predicate in EPIC is more complicated and complex than just conditional execution, its not entirely more useful IMHO, or at least that was my impression the last time I heard someone talk about it. Alpha has conditional execution. ARM has conditional execution. I can append checks to the condition codes in ARM assembly. I don't really understand why this is so nifty.

I've said it before, and I'll say it again. Resist the urge to think that whatever marketdroids tell you is new is actually good. Sometimes its not.

(If more knowledgeable people are lurking, please correct any errors I've made, but I think I've got this right.)