Multitasking and Quad Cores.

[TBard]

Well first of all sorry if the question has already been answered, but I haven't found a thing with the search and google (actually I found stuff about the argument but nothing that really answered me).
Here I go with the question...

I'm going to get a new rig, mainly for gaming, but I do a lot of multitasking too (even while gaming).
I know that as far as games as concerned most of them will benefit more now from a higher CPU clock than from 2 more CPUs, the fact is that as for now on my old AMD 64 3400+ around 15-25% of the CPU is used to run other application, even while I game, ranging from Firefox to IMs to Girder (for vocal commands and to send commands to other PCs in the net), also Sinergy and I could list more...
If I get a Quad core and manually route (using Vista affinity-thing, someone told me that's possibile, not sure since I still use XP) all those application and the system ones to a different CPU leaving 2 CPU dedicated only to games, would that make a Quad core a better choice or would you still go for the Dual Core?

Considering that I want to spend around 300€ for the PC (more or less) I think that the two most likely candidates as for now are the Penryn E8500 and the Q9450 (of course if you have other ideas just let me know )

 

[rockbyter]

XP and Vista can set affinity to any running process to run on a specific core, so you can start a game to use 1 or 2 cores, and manually everything else to use the other core(s) Dual core over single core makes a huge difference with basic multitasking like downloading pr0n while gaming. quad core is only necessary for more heavy duty things like virtualization while gaming, and/or 3d modeling. quad core sounds like overkill for what you describe, but having 4 now, means you dont need to upgrade later.

 

[skittle]

You dont have to manually set the affinity, xp and vista will both manage processor resources accordingly.

 

[geofelt]

Either will do unless your multitasking involves heavy cpu tasks or games like FSX. In that case a quad would be better. Certainly go for a new 45nm part, they are faster and cooler. Be certain that you have enough memory to hold all the tasks without interference; 4gb at least.

 

[TBard]

Dual core over single core makes a huge difference with basic multitasking like downloading pr0n while gaming. quad core is only necessary for more heavy duty things like virtualization while gaming, and/or 3d modeling. quad core sounds like overkill for what you describe, but having 4 now, means you dont need to upgrade later.

Well is that still true if we consider games that make full use of 2 of the 4 CPUs? (Like Age of Conan will, and I plan to play a lot of it)
Also another reason I'd rather go for the Quad is that I won't need to upgrade later when games will support it, but my fear is that when it happens I'll have a Quad with a clock speed to low to be worth it and may want/need to upgrade anyway.

Oh... and I have a dedicated server to DL prOn

 

[Kraynor]

Quads don't have bad clock speeds relative to Duals, they may not be as high but that's where overclocking comes in. Personally, I have the 'old' Q6600 running at 3.6 GHz in a water-cooled system, saving up some bucks for a 45nm quad to maybe bring that to 4.

Quads are worth it no matter what you do, in my opinion. Why have mundane tasks like anti-virus scans butting in on your gaming power when they can just be auto-allocated to an unused core

 

[b3n]

You can never have too many cores, eh

 

[rockbyter]

If nothing else, go quad core for the poor orphan children. They know you deserve it.

 

[Iscabis]

I have a Q6600, and it was definitely worth it. Software that takes advantage of multi-threading is increasing, and it is definitely nice to have the extra cores to speed things up when this software is encountered.

I recently upgraded my AVG 7.5 to 8.0, and the new version utilizes all four cores when scanning. 7-zip is multi-threaded, so it does too. Video encoding does as well. I also believe that most new games that come out now utilize all your cores. Eventually, it will be all new games that do this. When I play UT3, there can be up to 60% or so CPU power being used.

Quad core is a good choice I think, unless you really don't think the extra power will eve come in handy for you.

 

[Scotteq]

You dont have to manually set the affinity, xp and vista will both manage processor resources accordingly.

Quoted for Truth. You only need to set affinity if you only ever want the particular app to only ever run on a particular core. Ever... Only... yeah.... Both operating systems are intelligent enough to identify a resource hungry app - like your game - and give it it's own space. No User Intervention Required.

If you multitask lots, having a Quad will only help. The quality of your graphics counts a lot more for gaming performance than your processor. And if you want some numbers, you can always overclock a little.

 

[Amiga500]

You dont have to manually set the affinity, xp and vista will both manage processor resources accordingly.

Erm.


Its not exactly optimal though.


Everytime the OS moves the process from core 0/1 to core 2/3 the cache of the 2nd chip/die must be loaded from the 1st - which requires going through the FSB - which has far higher latencies. That (depending on app I guess) can result in pretty hefty performance hit - for some of the stuff I use, it is around 15%!

 

[skittle]

Erm.


Its not exactly optimal though.


Everytime the OS moves the process from core 0/1 to core 2/3 the cache of the 2nd chip/die must be loaded from the 1st - which requires going through the FSB - which has far higher latencies. That (depending on app I guess) can result in pretty hefty performance hit - for some of the stuff I use, it is around 15%!

please show proof of this unoptimized cpu! Im sure the intel engineers could use a few tips

The only time Ive ever seen an increase in speed from manually setting affinity was in quakeIII... on a AMD X2. it showed more than 2x increase in fps. Never such an issue from intel

 

[Guest]

Erm.


Its not exactly optimal though.


Everytime the OS moves the process from core 0/1 to core 2/3 the cache of the 2nd chip/die must be loaded from the 1st - which requires going through the FSB - which has far higher latencies. That (depending on app I guess) can result in pretty hefty performance hit - for some of the stuff I use, it is around 15%!

This is 100% true. Manually set your Cores for better performance.

 

[tstebbens]

please show proof of this unoptimized cpu! Im sure the intel engineers could use a few tips

The only time Ive ever seen an increase in speed from manually setting affinity was in quakeIII... on a AMD X2. it showed more than 2x increase in fps. Never such an issue from intel

Go and look at any of Tom's reviews of the quad-core Intel chips. It blatantly says all communication between cores 0/1 and 2/3 have to go via the FSB which must then be shared between the two sets of cores communicating with memory and the inter-core communication. A look at any of the architecture diagrams from Intel's site will also show this to be true.

 

[rockbyter]

2 instances of Folding@home single core plus 1 instance of folding@home GPU, if you do not manually set affinity for each of them - you will slow to a crawl and get very few points. After setting affinity the GPU will take off like a rocket. Actual Evidence of this? not setting affinity :
first single core instance = 2%-3% 11 min 4 sec.
Second single core instance = 2-3% 13 min 54 sec.
GPU Instance = 2-3% = 18 min 10 sec.

After Affinity :
first single core instance = 4%-5% 9 min 55 Sec.
Second single core = 4%-5% 9 min 34 sec.
GPU Intance = 5%-6% = 12 min 2 sec.

This is evidence enough for me that setting affinity works In some situations. To contradict me You could of course run a single instance of Super PI as is, then set its affinity and see if there is any increase or decrease. (at 8M digits, affinity set to a single core, or all cores, it finished in the same amount of time) 3min 43 sec.

If i am doing all those folding@home things at the same time using all cores - and play a divx movie with post processing on - i actually get a touch of choppiness setting affinity away from 1 core clears that up in a hurry. - wish i had a couple more cores to compensate for that - or run more folding@home. Maybe when dual-hexa or octacore processors are an option.

 

[blacksci]

I am gonna have to disagree with setting the whole affinity thing, I have a q6660 and play Company of Heros a fair bit, this game is a resource hog, 99% ram used. When im playing i have systems scans happen, and never ever notice until i end the game, and see the scan results, i also run 2 messenger services, and sometimes have a streaming video paused in the background,while using ventrillo and have never seen my game slow at all, not even the slightest hesitation. And when you look at gaming requirements for processors 90% of games still only require a core that is around 2.1 gig or so to run. So for your gaming standpoint since you are building a gaming computer, you arent going to have to worry, i understand other processess can slow down a quad, they can also slow down dual core, but for a gaming perspective quad core serves the purpose just great. Reason why most people say gaming is better on a duel core, is cuz they can overclock them higher then a quad usually, and the only time they see any diffrence is when they run there benchmarks. There is a point where you hit diminishing returns, and your only going to be able to achieve so much of a performance increase while overclocking, then its just a number game, i set my quad to 3.0 gigs and i load faster then most. Point being unless you have some insanely intensive project running on your quad, and you wont with gaming, not yet anyhow, you dont need to worry about assigning cores to run certain programs. Your os will handle that just fine for what you want to use it for, which is gaming.

 

[bobwya]

I am gonna have to disagree with setting the whole affinity thing, I have a q6660 and play Company of Heros a fair bit, this game is a resource hog, 99% ram used. When im playing i have systems scans happen, and never ever notice until i end the game, and see the scan results, i also run 2 messenger services, and sometimes have a streaming video paused in the background,while using ventrillo and have never seen my game slow at all, not even the slightest hesitation. And when you look at gaming requirements for processors 90% of games still only require a core that is around 2.1 gig or so to run. So for your gaming standpoint since you are building a gaming computer, you arent going to have to worry, i understand other processess can slow down a quad, they can also slow down dual core, but for a gaming perspective quad core serves the purpose just great. Reason why most people say gaming is better on a duel core, is cuz they can overclock them higher then a quad usually, and the only time they see any diffrence is when they run there benchmarks. There is a point where you hit diminishing returns, and your only going to be able to achieve so much of a performance increase while overclocking, then its just a number game, i set my quad to 3.0 gigs and i load faster then most. Point being unless you have some insanely intensive project running on your quad, and you wont with gaming, not yet anyhow, you dont need to worry about assigning cores to run certain programs. Your os will handle that just fine for what you want to use it for, which is gaming.

I am sorry but you are so totally wrong!!

I use AutoIt (http://www.autoitscript.com/) for scripting the assignment of cores for a dual-core Opteron machine. When I run multiple x264 encoding processes the speedup is enormous. Left to its on devices Windows moves the threads of the individual worker processes backwards and forwards between the two cores thrashing the CPU caches. Using system information view not only do the cores have higher average utilisation (99-100%) but the I/O transfer rate increases (i.e. the CPU's pull more data to process per second). This is not some bullshit benchmark but something that is tangable and makes a difference. I plan to move to quad core soon (2x dual-core Opteron) and hope for yet more speedup!!

The Windows is quite good at handling 1 CPU bound process (e.g. a single threaded game or encoding) moving processes that are I/O bound off the loaded core. When it comes to multiple CPU-bound processes it does not fare too well. It seems to have a system of moving the threads backwards and forwards between the cores like a game of pass the parcel!! This leads to CPU cache thrashing and loaded external bandwidth to RAM.

As an aside the task scheduler in the 2.6 kernel of Linux is much better designed than in Windows NT and uses a careful system of prioritising to ensure that all cores in a multiprocessor system are running a balanced load of processes/threads.

I would agree with people who say Quad core is a waste of money for the foreseeable future. Most people only need a dual core CPU.

Bob

 

[blacksci]

Actually im right, i was talking in regards to gaming, and real life experience, you folks are talking about apps hes not even interested in. And i have experienced this since i actually own the chip, not looking to upgrade to it in the future. Im really glad you have played with a system that in no way resembles the one he wants to build, and even took time to give us some percentages to impress us. Next time you want to throw in your two cents look at what i was pertaining too GAMING, its what the original poster was asking about, the rest of this is people making and argument about something hes not even interested in. Heres and idea, give your opinion if it is related to the topic, dont go off into left field about tasks hes hasnt even asked about, lets keep this pertinent folks.

 

[bobwya]

Actually im right, i was talking in regards to gaming, and real life experience, you folks are talking about apps hes not even interested in. And i have experienced this since i actually own the chip, not looking to upgrade to it in the future. Im really glad you have played with a system that in no way resembles the one he wants to build, and even took time to give us some percentages to impress us. Next time you want to throw in your two cents look at what i was pertaining too GAMING, its what the original poster was asking about, the rest of this is people making and argument about something hes not even interested in. Heres and idea, give your opinion if it is related to the topic, dont go off into left field about tasks hes hasnt even asked about, lets keep this pertinent folks.

Hold on a minute here....

Folding at home is not a minority activity and lots of folks rip DVDs to x264... Just because the guy talks about gaming doesn't mean he doesn't do other stuff on his rig... I certainly see higher FPS on a dual-core system with manual core assignment when encoding video. Games still tend to run as single main process - nobody is arguing with that fact. We are talking about dual versus quad core systems - the implementation is still very similar (although AMD might take slightly less hit from inter-core communication) - what do you mean we are talking about system that "no way resembles the one he wants to build"?? We are all talking about multi-core PCs - I don't see much difference myself... IT IS NOT A CONSOLE IT IS A GENERAL PURPOSE COMPUTER that can be used for things other than gaming. I use my computer for gaming, encoding, reading email, etc., etc.

If you are wrong why don't you just admit it instead of mouthing off to cover up the fact... Go and be boring elsewhere like the "I returned my E8400 today" thread...

Bob

 

[blacksci]

Ill let ya in on a little known secret, dual core and quad core both face the same issue, niether of them have a lot of programs out there for multithreading and the argument becomes moot at that point, sure you get higher overclocks with a dual core, thats bout it though. As far as me mouthing off i did it to get your goat, lol see it worked.

 

[skittle]

What are you using for the x264 jobs?

 

[lobofanina]

2 instances of Folding@home single core plus 1 instance of folding@home GPU, if you do not manually set affinity for each of them - you will slow to a crawl and get very few points. After setting affinity the GPU will take off like a rocket. Actual Evidence of this? not setting affinity :
first single core instance = 2%-3% 11 min 4 sec.
Second single core instance = 2-3% 13 min 54 sec.
GPU Instance = 2-3% = 18 min 10 sec.

After Affinity :
first single core instance = 4%-5% 9 min 55 Sec.
Second single core = 4%-5% 9 min 34 sec.
GPU Intance = 5%-6% = 12 min 2 sec.

This is evidence enough for me that setting affinity works In some situations. To contradict me You could of course run a single instance of Super PI as is, then set its affinity and see if there is any increase or decrease. (at 8M digits, affinity set to a single core, or all cores, it finished in the same amount of time) 3min 43 sec.

If i am doing all those folding@home things at the same time using all cores - and play a divx movie with post processing on - i actually get a touch of choppiness setting affinity away from 1 core clears that up in a hurry. - wish i had a couple more cores to compensate for that - or run more folding@home. Maybe when dual-hexa or octacore processors are an option.

Why are you still using the single threaded folding at home apps? With your rig in your sig you could average at least 2,000 points a day by just switching to SMP work. With your current setup I'm guessing you get 500-700 points per day.

I couldn't stand the unresponsiveness of my machine caused by running the gpufah prog no matter the affinity settings. I'm much more happy with with my 1950pro fahgpu in my torrent box.

Just curious happy folding, may your points quadruple overnight.

Brendan (lobofanina)

 

[Amiga500]

Actually im right, i was talking in regards to gaming, and real life experience, you folks are talking about apps hes not even interested in.

I assume you can name the applications he is interested in then?

I'm going to get a new rig, mainly for gaming, but I do a lot of multitasking too (even while gaming).

Sounds like a few extra cores wouldn't go amiss to me.





From my POV - a quad core is the only way to go really - name a game that is not GPU bound when it actually matters (i.e. anything below 60 FPS).


The future of game coding is multi-core, some games have it already, why buy a dual now and find out in a year or so a quad is needed. Then your having to pay out big money to get on the Nehalem bandwagon, or limit your upgrade cycle by just getting a Penryn quad.

 

[TBard]

Well I can name the app I'm interested in
I was talking about gaming in the first post because it's the stuff I spend my time the most and especially because I know already that for 3d modeling, video editing and such the 4cores are better.
My remaining doubt was if the quad would compare to the dual even though it has lower clock speeds in the case all other running apps were moved to cores 3-4.

As a matter of fact, because of my university, I have to do a bit of 3d modeling, audio and video editing and such, but since I don't do much of that it wasn't a reason enough alone to get a quad.
(After reading all that I decided for quad, hoping to find a Q9550 for a decent price at the expo I'll go next month, else I'll get the Q9450, still undecided on mobo though considering I still am undecided between 9800GX2 and 2x 9800GT)
Main reason for my decision is that I've made some test about the CPU usage of my background apps and the one I usually keep open while gaming and on my AMD64 3400+ @2.8ghz (or something like that, don't remember the exact clock I put it into ) it's around 25-30% and it easily go up to 40% usage when Girder decides to parse everything I say searching for word to confuse with commands (luckily Winamp/MPC/Torrents/etc run on another rig)

Meanwhile thanks again for the help and I'll go back to reading everything I find about new ram-mobo and GPUs (yes I wasn't following much the hardware stuff in the last year or so ). Feel free to add more if you want ofc I'll read everything

 

[Amiga500]

You aren't doing acoustics modelling with BEM are you?