Dual Core multitasking - how well is it working?

[CA_Steve]

Ok, a question for all of you that have dual core rigs - how well is it actually working in XP when running multiple concurrent applications?

Case in point - what about playing a CPU intensive game and also doing another cpu intensive task or two at the same time? Does it bog down the game (assumption is the two tasks aren't also competing for HDD time)?

[NeilBlanchard]

Hello Steve,

My Athlon 64 X2 4200+ (with WinXP Pro x86 & 2GB of RAM, btw) is very, very good at multitasking. I have run DataCAD (with multiple open files, and SketchUp, and FireFox, and two instances of Folding@Home -- all at the same time, and the machine remains very responsive, the whole time.

I'm happy with this machine.

[CA_Steve]

Thanks for the datapoint - too bad you aren't running macOS on it (just kidding)

[TomZ]

If you're a multitasker, dual-core is awesome. Once you use it, you'll never go back.

The benefit is as you assume, and confirmed by Neil, that when you run a program that needs 100% of the CPU, that you can still do other things with your machine. The machine becomes much more fluid and responsive, compared witih the choppy response from a single-core machine.

Even HyperThreading can give you the same effect, since it also avoids the issue of one thread consuming 100% of the CPU.

One thing you also have to think about is that, even when you just run a single-threaded application, this requires a lot of background work on the part of the OS. Therefore, this situation allows your application to run on one core and all the OS background operations to run on another core, more or less.

My last machine was dual processor AMDs, and my new one is Intel 955EE (dual core with HyperThreading). Also in the office we have some single-core HyperThreading machines, and the guys who use them like them much better than the single-core machines.

[quikkie]

two instances of climateprediction.net (BOINC project) at idle priority, some P2P program while playing serious sam 2 makes no difference to frame rates in SS2. See sig for rig details.

[~El~Jefe~]

The only lag in multitasking is from the harddrive or from a page not loading fast enough because of these retarded web banners.

Besides that, my 4200 with 2x1 gigs of memory is flawless.

and as for that claim that you can virus check and not see lag during a First person shooter, thats bogus. Just thought I would warn people You have to be running some really terrible game at like 800x600 to have that one work properly. You would have to asign tasks, which also isnt the way it should be done for gaming.


however, BF2 is MUCH faster on load times and in 64 person games, it is definitely smoother during gameplay.

[halcyon]

If you have a fairly well optimized system, lots of RAM, proper swap configuration and a decent CPU, the difference is NOT huge IMHO, unless you are constantly running two very cpu hungry apps.

But yes, it does increase smoothness, if you have an optimized system. For me the difference is not night and day though and load temps went up more than 20 degrees centigrade (even with increased cooling).

[stupid]

Ok, a question for all of you that have dual core rigs - how well is it actually working in XP when running multiple concurrent applications?

Case in point - what about playing a CPU intensive game and also doing another cpu intensive task or two at the same time? Does it bog down the game (assumption is the two tasks aren't also competing for HDD time)?

While I don't have a dual core rig yet, I think I can safely say that you shouldn't run into many issues if you are run two programs that are CPU intensive. The easy way to look at it is that one program will have an affinity for one CPU, while the other program will have an affinity for the 2nd CPU.

From a more complex perspective, a game or other application will not take up 100% of the CPU unless it is specifically designed to do so like Prime95. Often times both cores will not be utilized 100% by two applications. That is how Hyperthread works on the Pentium 4. So even with two programs running, there should still be enough processing power to mask any lag in performance. The real kicker is what happens if you are using 2 applications and both are optimized for dual core? At this point the situation may revert back to similar performance of a single core running multiple applications. At that point you'll may need to up the and and get quad core.

[quikkie]

From a more complex perspective, a game or other application will not take up 100% of the CPU unless it is specifically designed to do so like Prime95.

really? if a program wants cpu time and the OS isn't busy doing something else with that cpu resource then that program will take up 100% of the cpu. what you describe is the case of a program that hasn't expanded to fill all available resource - like using word 2 for dos versus word 2003 on todays PCs;)

The real kicker is what happens if you are using 2 applications and both are optimized for dual core?

this is commonly refered to as a "multi-threaded application", although by the time that marketing people are finished then it will probably end as "optimised for dual core" - similar to the win95 and winnt certified apps.

At this point the situation may revert back to similar performance of a single core running multiple applications. At that point you'll may need to up the and and get quad core.

I just had a vision of the future: 'slow' home computers specified in numbers of cpus ("what only 128 cores?") and spcr coming up with even more innovative (and possibly crazy) solutions to silence them

[TomZ]

From a more complex perspective, a game or other application will not take up 100% of the CPU unless it is specifically designed to do so like Prime95.

I agree with quikkie - I see a lot of times where I'm just running one application that is doing a lot of disk I/O, and it keeps two cores pretty busy (near 100%).

[stupid]

From a more complex perspective, a game or other application will not take up 100% of the CPU unless it is specifically designed to do so like Prime95.

really? if a program wants cpu time and the OS isn't busy doing something else with that cpu resource then that program will take up 100% of the cpu. what you describe is the case of a program that hasn't expanded to fill all available resource - like using word 2 for dos versus word 2003 on todays PCs;)

Actually I left out poorly designed programs. There are games that simply takes 100% of the CPU and barely allocates anything to background programs. If I play something like Age of Mythology on my Athlon XP 2600+ and convert video in the background, I get like 0.2 FPS even though the game only requires a PIII 450. On the otherhand I can play KOTOR and still do video conversion in the background at about 19 FPS.

The real kicker is what happens if you are using 2 applications and both are optimized for dual core?

this is commonly refered to as a "multi-threaded application", although by the time that marketing people are finished then it will probably end as "optimised for dual core" - similar to the win95 and winnt certified apps.

Yep, I know. But based on my experience I find that simply putting it in layman's terms is easier sometimes 'cause I sometimes get:

"Errrr.... multi-threaded... what's that?"

At this point the situation may revert back to similar performance of a single core running multiple applications. At that point you'll may need to up the and and get quad core.

I just had a vision of the future: 'slow' home computers specified in numbers of cpus ("what only 128 cores?") and spcr coming up with even more innovative (and possibly crazy) solutions to silence them

Hell, I waiting for my AMD 512 Core and Intel 512 Core combo super computer so that I can surf the net. Oh and add in a VIA C3 1.4GHz CPU somewhere, just to bring it that much closer to bleeding edge.

From a more complex perspective, a game or other application will not take up 100% of the CPU unless it is specifically designed to do so like Prime95.

I agree with quikkie - I see a lot of times where I'm just running one application that is doing a lot of disk I/O, and it keeps two cores pretty busy (near 100%).

Okay, but if you run another program like a video editor will the video editor still be capable of doing its job is it like watch paint dry on the front of your house while it's raining?

[TomZ]

Okay, but if you run another program like a video editor will the video editor still be capable of doing its job is it like watch paint dry on the front of your house while it's raining?

Sure, that would run on cores 3 and/or 4 on my machine. (I have a dual-core EE, so 4 virtual CPUs total.)

[halcyon]

Quick addition:

Many people (myself included) have serious issues with several games (due to dual core).

This is regardless of dual core processor drivers, MS hotfixes, registry edits or update of graphics drivers.

The problems manifest as speed-ups, stutters, crashes or other oddities.

Some have almost no problems at all, some several problems.

There are several lengthy threads about this in various forums (xtremesystems, hardocp, etc.).

The most working solution is to set the affinity of a process to a specific 1 core only (sometimes it _needs_ to be core 0).

This can be very tedious as you have to alt-tab out of the application (before problems occur) and set the affinity manually in Task Manager.

I have not yet to find a simple workaround for this, although I'm playing with AffinitySet.cmd + process.exe + sleep.exe right now.

[TomZ]

Many people (myself included) have serious issues with several games (due to dual core).

Most companies have worked out their software bugs by now, but to be sure, some programs probably haven't been tested and required fixes applied for dual-processor/dual-core.

[quikkie]

Quick addition:

Many people (myself included) have serious issues with several games (due to dual core).

I fixed a stutter problem with Serious Sam 2 that was seriously (pun intended, sorry) annoying. Call of Duty 2 also stuttered but not quite as badly. I used ChangeProcessAffinity, which I've uploaded to my webspace (60KB).

Change the shortcut to your game executable to call changeprocessaffinity with the right options (see the readme) and that should help.

[halcyon]

"Old" games (1st half of 2005 and earlier) usually don't get no new loving from their makers, unless they are hugely successful online games.

And even constantly updated games like BF2, CSS and WoW some people are having issues with.

So it's not all smooth riding to all, just FYI.

Otherwise I'm fairly happy with the dual core, but I'm really looking forward to Merom and getting rid of this Opteron heat pump :)

[quikkie]

"Old" games (1st half of 2005 and earlier) usually don't get no new loving from their makers, unless they are hugely successful online games.

true that. OTOH I have no problems playing Max Payne 2, Half Life 2, Call of Duty, F.E.A.R. or Solider of Fortune 2. BF2 runs without any problems other than those dodgy patches that EA put out, but that's a rant for another time and place. The only games I've had to use any process affinity trickery on is SS2 and CoD2 - that's it!

[TomZ]

Anyone have an general opinion about what setting the process affinity makes these programs "happy"?

[quikkie]

just setting it to one processor or the other means that the game code isn't swapping around the cpus which I think is what it causing the problems I had.

Personally I set it to the second cpu just umm "because", no technical reason behind it at all

[~El~Jefe~]

"Old" games (1st half of 2005 and earlier) usually don't get no new loving from their makers, unless they are hugely successful online games.

And even constantly updated games like BF2, CSS and WoW some people are having issues with.

So it's not all smooth riding to all, just FYI.

Otherwise I'm fairly happy with the dual core, but I'm really looking forward to Merom and getting rid of this Opteron heat pump

Merom might be ok, but conroe will produce as much or more heat than a properly adjusted 90nm Opteron.


Intel made the chips to out PERFORM amd and not exceed current heat output. It has been tested time and time again that a Dothan running at 2.5 ghz (oc'd) puts out as much heat per performance as a 90nm fx series.


Back to the dual core: Vampire Bloodlines has gotten SUPER slow in some cases on account of the dual core. Other times, it is sped up greatly with the dual core. COD, halflife2 and vampire should speed up nicely with dual core as its engine is unique in the sense that it offloads graphics processing to unused cpu resources. ...and it does work except for two scenes in the game. I wish I knew more about programming, the occurence seems not at all random and probably could shed some decent light on what types of situations dual cores suffer in.

Still, i wouldnt give it up. WIndows in general is 3x faster in almost every way.