to those who own dual processor rigs

[Brian23]

Do you find there to be any benefit in having a dual processor system over a single processor system?
What do you use your computer for?

 

[Mik3y]

yes, of course the 2nd chip really helps. instead of having only 100% cpu bandwidth, it allows for 185%ish. one cpu is then dedicated for the os, and the other for apps. this allows for MUCH greater multi-tasking. not very many games take advantage of multi-cpus because they are single threaded (at least for now), so a dually setup for gaming is currently not worth it. the primary advantage is basically multi-tasking. if you want more info, just ask markfw900. he has a dually opteron setup does everything with it, including folding at home.

 

[Colt45]

I used to have a dual system a couple years back.

i can't really describe it.. it doesn't feel much faster, it feels like it has more torque.. if you know what i mean. 😕

 

[Chaotic42]

If you do lots of heavy multitasking (Photoshop, 3DSMax, CAD, etc), it's almost a requirement. It doesn't make the computing experience feel faster, it makes it smoother.

 

[Mik3y]

like the other guys said, it doesnt perform faster. it just performs better.

 

[SUOrangeman]

I know it is overkill, but I have a dual 2GHz Athlon system here at home. I hardly game, but I don't "work" from home either. There is just a creamy smoothness that I don't get from "faster" single-CPU systems at work (2.8GHz at my desk, a few 3.0/3.2GHz in the lab).

I intend to upgrade to the Iwill zMAXdp (dual-Opteron, still for home use) once prices stabilize. Why? Just because I can!

-SUO

 

[vegetation]

Only had one way back in the BP6 days, with dual 550's. It was quite a nice experience, as the system never had that lagging feeling as does single processor systems under heavy load. It just kept going on strong, as if it were a mainframe or something 😉

 

[imported_Phil]

Originally posted by: Mik3y
one cpu is then dedicated for the os, and the other for apps. this allows for MUCH greater multi-tasking.

Sorry, but that's entirely wrong.

Both CPUs do whatever they're told. Windows doesn't allocate one to Windows and one to apps; that wouldn't make any sense whatsoever. For instance, if you're running Folding @ Home which is pegging one CPU at 100%, and then start another program, the two programs aren't going to fight over that same CPU, they're going to run mostly on one each, or however Windows sees fit to distribute the threads amongst the available processors.

I assume that you haven't ever actually used a dual-CPU platform, because if you had then you'd know that when you're running a multi-threaded application, you'll see that both CPU graphs in Task Manager are showing load, as opposed to just the one.

Here's a screengrab of the CPU graphs of our Forums server at work that I maintain. This was taken directly after running a database backup of phpBB2- notice the loads are for both processors, not one.

 

[Sunner]

Originally posted by: Dopefiend

Originally posted by: Mik3y
one cpu is then dedicated for the os, and the other for apps. this allows for MUCH greater multi-tasking.

Sorry, but that's entirely wrong.

Both CPUs do whatever they're told. Windows doesn't allocate one to Windows and one to apps; that wouldn't make any sense whatsoever. For instance, if you're running Folding @ Home which is pegging one CPU at 100%, and then start another program, the two programs aren't going to fight over that same CPU, they're going to run mostly on one each, or however Windows sees fit to distribute the threads amongst the available processors.

I assume that you haven't ever actually used a dual-CPU platform, because if you had then you'd know that when you're running a multi-threaded application, you'll see that both CPU graphs in Task Manager are showing load, as opposed to just the one.

Yeah, one funny thing I keep seeing is people talking about the major benefit of having the various OS processes running on one CPU, freeing the other one up.

People should just take a look at their task manager to see just how much CPU their OS is eating.
If it's more than ~1% when idle, I'd say something funny is going on.

 

[imported_Phil]

Originally posted by: Sunner

Yeah, one funny thing I keep seeing is people talking about the major benefit of having the various OS processes running on one CPU, freeing the other one up.

People should just take a look at their task manager to see just how much CPU their OS is eating.
If it's more than ~1% when idle, I'd say something funny is going on.

It's frustrating, to say the least- although I suppose if more people had an idea of how the OS passes threads to the processors, then this misconception might be a thing of the past. Here's hoping :beer:

 

[imported_Phil]

Originally posted by: SUOrangeman
I know it is overkill, but I have a dual 2GHz Athlon system here at home. I hardly game, but I don't "work" from home either. There is just a creamy smoothness that I don't get from "faster" single-CPU systems at work (2.8GHz at my desk, a few 3.0/3.2GHz in the lab).

I intend to upgrade to the Iwill zMAXdp (dual-Opteron, still for home use) once prices stabilize. Why? Just because I can!

-SUO

:thumbsup:

There's an old thread floating around in which I detailed my findings with a quad Opteron 248 server that was on loan to us. 3.5Gb RAM, four 248 beasts, four-disk SCSI U320 array, etc.
Now that thing was fast. Once Gentoo was done installing & compiling (Stage 1 😀 - I've never seen anything make Xfree86 so damned quick), the responsiveness and smoothness couldn't be touched by anything else we had in the office at the time.

Although it's a poor comparison, I put it up against a dual 2.8Ghz Xeon server that Intel had lent us to evaluate, and it urinated all over it.

 

[Matthias99]

Originally posted by: Dopefiend

Originally posted by: Sunner

Yeah, one funny thing I keep seeing is people talking about the major benefit of having the various OS processes running on one CPU, freeing the other one up.

People should just take a look at their task manager to see just how much CPU their OS is eating.
If it's more than ~1% when idle, I'd say something funny is going on.

It's frustrating, to say the least- although I suppose if more people had an idea of how the OS passes threads to the processors, then this misconception might be a thing of the past. Here's hoping :beer:

Well, apparently some *NIX variants do this (or at least *used* to do this at some point). With WinNT/XP/2K, though, it's definitely not true. OS threads can be scheduled on either processor, as can user threads.

 

[uOpt]

It helps with compilation is you remember to use -j3 (and trust your makefiles).

Overall I don't think it's worth it, the only reason I have an older SMP system at home is that I need it to test things in FreeBSD SMP.

The major problem is that CPU upgrades get twice as expensive and the old CPUs are harder to sell. Performance for the money wise, SMP is usually not an advantage long-term.

In actual professional terms, SMP offers the biggest advantage if you have multiple parallel processes access the same data. That is pretty rare for home usage.

 

[imported_Phil]

Originally posted by: MartinCracauer
The major problem is that CPU upgrades get twice as expensive and the old CPUs are harder to sell. Performance for the money wise, SMP is usually not an advantage long-term.

This is the reason that I haven't looked at an SMP machine myself- it's just too darned expensive.

 

[Brian23]

Originally posted by: Dopefiend

Originally posted by: MartinCracauer
The major problem is that CPU upgrades get twice as expensive and the old CPUs are harder to sell. Performance for the money wise, SMP is usually not an advantage long-term.

This is the reason that I haven't looked at an SMP machine myself- it's just too darned expensive.

Just wait until the dual core Athlon 64s come out

 

[imported_Phil]

Originally posted by: Brian23

Originally posted by: Dopefiend

Originally posted by: MartinCracauer
The major problem is that CPU upgrades get twice as expensive and the old CPUs are harder to sell. Performance for the money wise, SMP is usually not an advantage long-term.

This is the reason that I haven't looked at an SMP machine myself- it's just too darned expensive.

Just wait until the dual core Athlon 64s come out

Ah, too true. However....

Damnit. I can't think of a good reason why not.