What Happened To Moore’s Law?

2008.03.17   prev     next

Slashdot reports that a new design may produce computer chips that are ten times as power efficient as current designs. I should say hooray, but why, instead, do I feel a sense of increasing dismay?

I’m no processor-chip expert, but I’ve been getting a bad feeling in the past few years that processing power in desktop computers isn’t increasing much. Certainly not the “Moore’s law” kind of increases I was getting used to.

A typical desktop PC these days has what — a dual-core, maybe 1.5 Ghz processor in it? So if my software is perfectly optimized for multi-processing, then I get what: 1.5 Ghz times 2 cores equals 3.0 Ghz. Wait a minute — haven’t we been hearing about 3 Ghz chips for several years now? (And those chips didn’t require perfectly optimized multi-processing apps!)

Watt?

Now, I’m aware that recent years have seen a huge boost in “performance per watt.” Recall Steve Jobs’s speech explaining his reasons for dumping PowerPC for Intel. (I’m sure he had good reasons to do that, and I don’t doubt that it was the right decision.)

But what does performance-per-watt do for me when I’m at my desktop computer? The computer that doesn’t run on a battery? Does it shave a couple dollars off my electric bill? Does it give me a warm fuzzy that I’m “saving the planet” — by using a few dollars less electricity per month!? And for those dubious benefits I’m supposed to forsake running my apps at multiples of the speed at which they’re currently running?

Maybe I don’t know enough about these chips. Maybe I’m talking out of my ass. Or maybe in the next few months Apple is going to release quad-core iMacs and Minis at the same prices as today’s dual-core versions, and maybe they’ll be running at 2 Ghz per core. That would shut me up in a hurry.

In the meantime, I’ll just sit here and worry that the Moore train has been derailed.

Update 2008.03.17 — OK, I just found out that I’m a bit behind the times: The cheapest iMac runs at 2 Ghz. But still, that’s the equivalent of 4 Ghz (assuming perfect theoretical exploitation of multiprocessing), which is just 33% faster than 3 Ghz that was available years ago. Throw in another, identical processor (for 4 cores total), and it would be a substantial improvement; equivalent to 8 Ghz when perfectly used by apps, and 6 or 7 Ghz if sub-optimally (i.e. realistically) exploited.

Update 2008.04.28 — New iMacs just came out today, and they run a dual-core processor at just over 3 Ghz (if you buy the fastest model). 3x2 isn’t as good as 2x4, but at least single-threaded code can now run at up to 3 Ghz. Getting there!