Is Dell really making a 2nd cpu for free offer?
On the general issue of what a 2nd processor gives you, here's a couple year old articles from Anand: anandtech.com
anandtech.com
As near as I can tell, the 2nd CPU doesn't add much except in specialized applications, and even there you never get anything like a 2x improvement. The 2nd article has a strange conclusion that doesn't seem to match the graphs at all. In general, a 50% faster CPU will win all the time, and be close to 50% faster most of the time, when things are CPU bound.
I got a vintage dual PPro system, and my personal experience is similar. I looked at the task manager CPU chart, running 100% processor stuff, and it's amusing, the usage charts for the 2 cpu's will go into this random inverted image pattern, where cpu1%usage + cpu2%usage = 100.
Linux is a little different, there are some things that can be parallelized fairly trivially, the favorite of software jocks is kernel recompilation. This will often show a near linear improvement, i.e. it will go close to twice as fast with dual processors. And the way X works, you could expect some improvement in anything graphic intensive, since sending bits to the display is always done in a separate process from the application.
Servers are different too, you'd normally expect extra processors to be useful there, though scaling usually works better in Unix than NT, just because Unix programmers aren't shy about starting lots of processes, where NT tends to run single tasks with multiple threads. NT task switching is really piggy, and NT thread switching is not cheap either.
Cheers, Dan. |
