Gaming through single vs dual core processors

[Latrobe]

I have a dual-core processor and I'm wondering what is the difference of running a game through one processor vs two processor? Is there even a difference? I've been reading about this recently and from what I've read (so far) you can run a game through one processor and run your background stuff on the other processor. This would increase your game speed since there is less activity going through the one processor, correct? I may be completely wrong about this though.

What difference does it make if you run a game through one processor or if you run it through both? Or, does it make no difference and I'm just wasting my time?

[gyrene81]

geez, there is such a large number of variables that have to taken into consideration with your question. in very generalistic terms, yes you could have a game use just one or two cpu cores and have all other processes/applications run on the others. also just generally speaking core speed will make more difference in program performance than the number of cores available. according to htc, ah will only use a maximum of 2 cores on intel cpus and only 1 core on amd cpus, so the speed of each core makes a lot of difference. the operating system has processes that will use all available cores and some programs/games will as well. if a program has the ability to be directed to a specific cpu core, then it's best to have it do so if you want to be able to multi task and maintain overall performance.

again, that's in very general terms. what is it you're trying to do anyway?

[Ripsnort]

Someone please confuse him more with quad core processors

Signed, Ripsnort who used to used to burn ants on the sidewalk with a magnifying glass ....

[100Coogn]

If you have an AMD processor, AHII will only use one core IIRC.

Coogan

[dedalos]

If you have an AMD processor, AHII will only use one core IIRC.

Coogan

Interesting.  Anyone knows why?

[Maverick]

Someone please confuse him more with quad core processors

Signed, Ripsnort who used to used to burn ants on the sidewalk with a magnifying glass ....

Used to only because his Mom took his maginfying glass away yesterday.   

[Shuffler]

Multi core processors allow multitasking better.

Add to this your graphics cards processor and it is spread around rather than all through one point. Single core has to cycle multiple tasks through meaning each is slowed a little.

Program X
Program L
Program Z

Single core    XLZXLZXLZXLZXLZ


Quad Core      XXXXXXXX
                    LLLLLLLLL
                    ZZZZZZZ
                    ________  << at rest


A bit simplistic but basically how it works.

[68ZooM]

anyway to assign programs to seperate cores, or does this happen on its own? i've always wondered about quad cores ( i have a quad core AMD)

[gyrene81]

Interesting.  Anyone knows why?

skuzzy has mentioned it in several discussions under the hardware section, something about a "bug" in amd multi-core cpu's, it may be related to using nvidia chipsets and/or graphics cards or just the cpu's themselves. i believe tequila chaser has the baddest amd system running right now with the latest amd 890 chipsets and he has said ah is only using a single core on his system.

obviously ah will run better on a dual core 3+ghz intel cpu than it will on a 3+ghz quad core amd, but with the right combination of parts ah will run very well with an amd.

[Wiley]

What I'm getting from Latrobe is he's wanting to manually assign which core(s) are being used by which tasks.

Logically speaking, it would seem to me to make sense on a dual core system (for example) to have the OS processes running on one core, and AH running on the other.  Quick, cursory googling indicates to me that Windows doesn't appear to like it when people assign the processor for system processes manually so I doubt a person would be able to set it up that way.  In any case, if you assign it manually it only takes for as long as the program is open.

It's a nice thought, but I suspect allowing the OS to do whatever it does may be the better choice.

Wiley.

[Tigger29]

OK here's the deal with cores.  Each core is like a separate processor.  If a program isn't specifically designed to run on multiple cores it will only use one core, *BUT* since other programs that may be running can use the other core(s) it can still make a difference.  However if a program is designed to use multiple cores then it will take advantage of them all even though it's technically one program but since programs often have to do multiple things at once this can prove to be a definite improvement in performance.

Think of it like a highway.  The processor speed is like the speed limit and the number of cores is like the number of lanes.  If there is only one car on the highway it's going to go the speed limit regardless as to how many lanes there are.  If there is a lot of traffic then then things will start to get backed up pretty quick unless they start using more lanes.  Having multiple lanes allows for more traffic to occupy the same road without slowing it down.

Now lets say you have a really big program... which in this example would be like hauling a double-wide trailer-home on that highway.  Even with no other traffic if there is only one lane they would have to cut it in half vertically and run two trucks because it wouldn't physically fit on the road.  If there were two lanes then they could occupy both lanes and make the trip without having to split it up.  Of course a custom truck would be needed that can run on both lanes at once but it could still be done.

And using that example with Aces High... well it can run on one core but it is designed to take advantage of up to two cores if need be.  I don't know about the whole single core AMD thing you guys keep mentioning.  I know on the older AMD processors you had to limit it to one core in order to prevent issues but I thought that had been resolved a couple of years ago.  I don't use an AMD processor so I don't really know for sure but it would be nice to hear something official about this.

So if Aces High only uses two cores then why would you want to run a processor with even more cores?  Well there is still a little bit of performance to be gained because even though Aces High will use both cores, if you only have a dual core processor then the other Windows functions still have to share those two cores with Aces High as well.  If you have a three core (or more) processor then it can leave two cores dedicated to Aces High and still run other functions on the remaining core(s).  How much of a difference this really makes is debatable and the general consensus is that if you have to choose between a slower quad-core or a faster dual-core processor than the faster dual-core processor will yield a higher performance gain.  Since dual cores are now pretty much "yesterday's technology" this is probably a moot point for anyone building or upgrading a system.

While it is possible to manually assign specific programs to specific processor cores there really is no need to do so.  It does a pretty decent job of managing all of this automatically.

[1701E]

Interesting.  Anyone knows why?

skuzzy has mentioned it in several discussions under the hardware section, something about a "bug" in amd multi-core cpu's, it may be related to using nvidia chipsets and/or graphics cards or just the cpu's themselves. i believe tequila chaser has the baddest amd system running right now with the latest amd 890 chipsets and he has said ah is only using a single core on his system.
obviously ah will run better on a dual core 3+ghz intel cpu than it will on a 3+ghz quad core amd, but with the right combination of parts ah will run very well with an amd.

As Gyrene mentioned, it's a "bug" of sorts.  I asked Skuzzy once, and hopefully he doesn't mind me posting this but a brief exert was:

"I cannot say a lot, due to non-disclosures with AMD. [. . .] The problem with Aces High is the use of multiple high resolution timers in
conjunction with threading." - Skuzzy

[Latrobe]

This is all very interesting stuff. As Wiley said, I am asking about manually assigning programs to a certain processor. After some more reading though, it seems that after you close the program, all setting changes you did return back to default. So if I set the game "Minecraft" (for example) to run only on processor 1, then it'll run using only that processor. However, once I close Minecraft the settings will return back to default and Minecraft will use both processors the next time I play it unless I manually change it again.

From what I'm hearing, running a game on both processors gets better performance. When I buy a new computer (which I plan to some time soon hopefully) should I buy a quad-core or is a dual-core just as capable to run high end games like Aces High, Rise of Flight, or BF3?

[Skuzzy]

Tigger, your analogy is close, but missing one bit of data.  There is only one lane to and from the system RAM.  Any time a core needs to read or write to system RAM, all other cores must wait before they can access system RAM.

Like a one lane bridge that can only hold the weight of one car at a time.

The AMD issue is not as big a problem as it used to be.

[Ack-Ack]

Interesting.  Anyone knows why?

It's a bug with the AMD chips.

ack-ack