For 99% of what I do, my 700 MHz Dell is plenty fast. The exception is simulation, either Spice or home-made stuff. For decent human feedback, you need to see the result of a change within a few seconds. I occasionally run into circuits that need 20 minutes to simulate one transient, so I'd like roughly 1000x what any Pentium can currently deliver. I'm simulating ion paths at 1 fs time steps, over a 500 ns flight, times 10,000 ions for a Monte Carlo thing, and it gets tedious. Things like Spicing oscillators can be equally bad.
John
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F
Floyd Davidson
Your application is just an _ideal_ example of what my point about cpu speed means. Your simulation that takes 20 minutes would be reduced to 10 minutes if you can get a 100% speed increase. That won't make you satisfied, but it would certainly be "significant".
On the other hand a 10% speed increase won't even be noticed, because you probably hit and go make a cup of coffee or something, and half the time may not notice when the job is finished for longer than 10% would shave off the time!
On the other hand... a 4x increase in speed would reduce that run to 5 minutes. You can go get a cup, but you just barely have enough time to make a pot if that is required, and if so you won't get a chance to drink it. *That* is real significance!
My way of looking at it is that if some modification will give me 2x the speed, I'll do it if it is dirt cheap. At 4x increase, I'm interested if it doesn't mean essentially replacing the whole box. If I'm going to buy a while new computer, I want to see something like 6x the speed.
Floyd L. Davidson
Ukpeagvik (Barrow, Alaska) floyd@barrow.com
J
John Larkin
Yeah, something like 3-4x is worth an upgrade if you are really compute-bound enough to be annoying. I'd guess that few people are these days. Who needs speed? Game players and Spice simulation come to mind, maybe animation or something, too. Most PCB or mechanical CAD seems fairly happy at 700 MHz, although SolidWorks can get might slow painting or rotating a complex structure.
I occasionally get a PDF page that takes minutes to view or print; very strange.
John
C
CJT
I think that's about right. I stuck with my 200 MHz Pentium Pro until the 1400 MHz Athlons became cheap.
After being targeted with gigabytes of trash by the "SWEN" worm, I have
concluded we must conceal our e-mail address. Our true address is the
mirror image of what you see before the "@" symbol. It's a shame such
steps are necessary. ...Charlie
S
Spehro Pefhany
Previous generations, my rule of thumb was 3:1, but I waited more like your number last time. The difference just wasn't that important for most things.
For things like CAD, the use of a fancy video card might be more important than the clock speed. They can cost more than an entire "2.4GHz" system.
Best regards, Spehro Pefhany
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
W
w_tom
My ballpark observation was that CPU speed has to increase on the order of 8 times for the human observed response time (for program execution) to double.
A lack of multimedia demand in the late 1990s means that CPU speeds have gotten ahead of demand. IOW had broadband been available in late 1990s as the industry had expected, then CPU speed would have been a bottleneck. We are only into broadband today about where they expected us to be about
1997/8.
Spehro Pefhany wrote:
D
DarkMatter
On Thu, 04 Dec 2003 09:40:55 -0800, John Larkin Gave us:
Sounds like you'd be better off writing your own sim for it.
I
Ian Stirling
If it melts and runs out, you've put too much in, and it's just squeezing out the excess.
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