My quad-core CPU is useless

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03-09-2011
VirtualAce

My quad-core CPU is useless

The new fad is the more cores the better. However I'm finding that time and time again I must set my processor affinity down to 1 CPU in order to get most of my games to run without massive stuttering and glitches. It is not a framerate issue b/c I'm pulling in 60 FPS on 60Hz yet the games still stutter. The moment I set the affinity the games are smooth as silk.

It seems that not many games are actually utilizing multi-cores or are designed with multi-threading in mind.

This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.
03-09-2011
itsme86

Quote:

Originally Posted by Bubba

The new fad is the more cores the better. However I'm finding that time and time again I must set my processor affinity down to 1 CPU in order to get most of my games to run without massive stuttering and glitches. It is not a framerate issue b/c I'm pulling in 60 FPS on 60Hz yet the games still stutter. The moment I set the affinity the games are smooth as silk.

It seems that not many games are actually utilizing multi-cores or are designed with multi-threading in mind.

This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.

I haven't noticed the same problem. I'm running a Core i7-920 and games seem to run fine. I do agree with you assessment about the lack of multi-threading in games though. Maybe the 'more cores' fad is the CPU maker's last hope of selling more merchandise in a 'we can't make it any samller' or 'we can't dissipate the heat the any faster' world. It wasn't too many years ago that I remember constant, drastic increases in core clock speed, but it seems that for the past couple of years we've had a ~3GHz plateau.
03-09-2011
Neo1

Quote:

Originally Posted by Bubba

The new fad is the more cores the better. However I'm finding that time and time again I must set my processor affinity down to 1 CPU in order to get most of my games to run without massive stuttering and glitches. It is not a framerate issue b/c I'm pulling in 60 FPS on 60Hz yet the games still stutter. The moment I set the affinity the games are smooth as silk.

It seems that not many games are actually utilizing multi-cores or are designed with multi-threading in mind.

This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.

I've never run into this issue with my i7, the problem you describe sounds like microstuttering, though that usually has someting to do with multi-gpu rigs. I have however had to force some older games to run on one core only, for them to even launch properly, but that is to be expected imo.
03-09-2011
Mario F.

Microstuttering was my first thought too. Definitely not an issue with processor affinity (based only on my experience of never having suffered from it). And it's just not an issue with dual GPU. Single GPUs can also experience it, apparently due to game engine bugs(?). Check this example (search that text for "micro").

edit: Incidentally, if your CPU supports it what happens when you disable hyper-threading?

Quote:

This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.

Oh absolutely! I've been saying that for quite some time. The threading model is pure evil (pdf). Threads are why I got to admire so much the concurrent model of Erlang.... It doesn't use them. :)
03-09-2011
VirtualAce

I am noticing a common thread in most of the micro-stutter posts. They are almost all using AMD Phenom 2 quad-core CPUs. I have an AMD quad-core AMD Phenom 2 940 and have buckets of microstutter in my games.

My hard drive is squeaky clean as I use Diskkeeper to keep it nice and defragmented along with a few boot time defrags which are very thorough. I have no viruses, no spyware, etc. and my system processes are down to 26 or 28 at boot.

I could never prove it to AMD and AMD would blame NVidia and NVidia would blame AMD and Microsoft would blame them both....but I suspect it is an issue with the quad-core Phenom 2 that is starting to rear its ugly head as more and more people opt for the slower yet comparable and much cheaper AMD Phenom 2 over the I7. It really sucks though b/c my rig is built for gaming and pretty much has everything from the DRAM to CPU to the GPU overclocked. Perhaps it is time to move back to Intel.
03-09-2011
brewbuck

Parallelism is the only way forward. IMHO, the complaints about difficulty writing correct parallel code are the same sort of whining as the people who put off the switch to 32-bit for as long as possible (the same of course is now happening with 64-bit).

It's difficult, but that's because programming is difficult.
03-09-2011
nimitzhunter

Seem like noone has asked this yet. But, what kind of games are you playing? and is it any fun? i'm looking for something to play.
03-09-2011
Yarin

Quote:

Originally Posted by nimitzhunter

Seem like noone has asked this yet. But, what kind of games are you playing? and is it any fun? i'm looking for something to play.

Considering the sheer number of games out there, I'm surprised that you'd have to derail a tread just to find one. But since you asked... try Nexuiz. :)
03-09-2011
VirtualAce

Please stay on topic.
03-10-2011
phantomotap

I have a similar rig, according to your other posts. It isn't a gaming rig, but what bits and bobs I've tried haven't stuttered.

Now, I've seen all kinds of tearing and wrong or missing textures, but I blame the crappy use of "Unreal 3" and "CryEngine" for that. (By this I mean that the developers are using those tools poorly.) Then again, I use drivers that are 3-6 months old, or older, at any given time.

Oh, but I do agree that the design of the threading model really needs work.

Soma
03-11-2011
zacs7

Don't forget it could have nothing to do with the CPU itself -- more the controlling chipset or the bus.

As an aside, it's interesting to see the new languages/features and frameworks that make multi-threading a tad easier like Go or C# 4.0.
03-12-2011
VirtualAce
I'm not sure what is causing the micro-stutter but I wish I could find it. It is not present in all games but many of them do suffer from it. I'm going out on a limb here but my 1TB drive only has about 15% left. Could that be causing the issue. Frankly I do not see how that could cause the problem but I'm open to anything at this point. I just dropped my texture quality to quality instead of high quality so perhaps that will change some things. I'm running a GTX 465 1024mb card so I should not be having any issues.

Games that micro-stutter so far:
- NBA 2K11 - some arenas are nearly unplayable
- Fallout 3 - probably due to Gamebryo which is known to stutter and frameskip
- Divinity 2 - again uses Gamebryo
- Saints Row 2 - known to stutter when driving but mine stutters when walking
- Mercenaries 2 - also known to stutter on certain machines when driving - mine is one of them, yay me
- Test Drive Unlimited 2 - only stutters in certain areas of Oahu and Ibiza..not all areas
Games that are smooth as silk
- Stalker - all versions and all sequels
- Crysis
- Far Cry 2
- All Need For Speed games
- Burnout Paradise
- NBA 2K10
- MLB 2K9 and 2K10
- Microsoft FSX (within reason and when not in large cities)
- Sims 3
- Dragon Age Origins
- Drakensang
- Risen
Does this come down to an engine optimization issue or do you think there is something else going on?
03-12-2011
Mario F.

I would put my money all on exactly an engine optimization issue (why, below). I think the processor affinity setting change only helps indirectly and does not reveal a problem with the processor (in fact because it helps you, the processor only shows how much of a solution it is). You are effectively taking more advantage of your cache by setting the affinity to 1 core and hinting the CPU to use that core as much as possible, thus mitigating the effects of your stutter. I think you know all this otherwise you wouldn't be messing with processor affinity. What I suspect you aren't remembering is that this is very close to what would happen if you could somehow set IFPSClamp to a minimum setting and said that only frames below that setting should obey it (some sort of iFPSClamp for slower frames forcing them to remain on screen until the next frame is ready). Essentially you are removing (or minimizing on the case of processor affinity) skip-ahead which is the visible effect of stutter.

This will probably could have a negative impact on the portions of the game that are multi-threaded. But being that you have such a powerful system (and processor affinity is after all just a hint, not a written-on-stone setting) that goes unnoticed. Besides, processor requirements for modern games are, after all, still very modest.

Anyways, the fact processor affinity helps is why exactly I believe this is an engine issue. With the exception of SLI and CrossFire configurations which do microstutter but for other reasons, the fact you are experiencing this on a single GPU can only be attributed to the game engine, excluding of course any defect of your graphics card (which we can exclude because it can run crysis -- old joke :p).

Why however you experience and I don't -- why person A does, and person B doesn't -- is a mystery to me. However I hear of community developed mods for games like Oblivion and Fallout 3 that do successfully remove microstuttering. So this is one hint that no matter other reasons, definitely the engine has a saying about all that. And because you can run the cryengine without a glitch is yet another reason to believe so.
03-13-2011
happyclown

Who is Virtual Ace? What happened to Bubba Bongo? :D
03-13-2011
Cat

Quote:

Originally Posted by VirtualAce

It seems that not many games are actually utilizing multi-cores or are designed with multi-threading in mind.

This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.

The problem is that most games generally aren't going to thread well in general. It's not usually efficient at all to have multiple cores doing the same task - the time spent on synchronizing will more than eliminate the benefit of utilizing multiple cores. Games don't usually have a lot of computations that can be run asynchronously from the rendering loop; everything except the rendering loop can be pushed into another thread and that thread would typically only take a small fraction of one core.

Maybe if you had a game with a complex physics engine that could be pushed off to another core and get some benefit, but that's about the only case I can think of.
03-14-2011
phantomotap

See articles on threaded AI techniques and lock free data structures.

Quote:

* NBA 2K11 - some arenas are nearly unplayable
* Fallout 3 - probably due to Gamebryo which is known to stutter and frameskip
* Divinity 2 - again uses Gamebryo
* Saints Row 2 - known to stutter when driving but mine stutters when walking
* Mercenaries 2 - also known to stutter on certain machines when driving - mine is one of them, yay me
* Test Drive Unlimited 2 - only stutters in certain areas of Oahu and Ibiza..not all areas

I don't have any of those, but I do have "Bully". I get no stutter from it, but I guess that could just be different people making different changes.

Quote:

Who is Virtual Ace? What happened to Bubba Bongo?

And more importantly, may we call him Bace?

Soma
03-15-2011
BobMcGee123

I just think this is interesting because I'm running into similar problems, although not with games, but with ANSYS 13.0 mesher. At most, it uses 12% (7 other cores not being utilized, or under-utilized), the shared memory (as opposed to message passing) full enabled, it turns out that, hey, tough luck, some of the algorithms just can't use all ya got.

[ANSYS Meshing] Optimizing CPU usage -- CFD Online Discussion Forums

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