How does your dual core CPU perform?

[Day03]

I've had my AMD x2 4200+ dual core cpu for a few month now and I'm happy with it but I don't think it's as good as many people say it is. Before I bought it there was all this hype that you can perform two tasks simultanously and you will not notice any slowdown. This is not true at least in my case, running two cpu intensive tasks at the same time does slow each other down quite considerably. For example extracting two movies at the same time from a RAR file does take longer that extracting them one at a time. How is everyone else finding their dual core cpus? Can you extract 2 very large RAR files simultanously without any slowdown?
I'm wondering if it's just me or are those cpus like that. I do have alll the latest driver and patches installed including the one from microsoft.

 

[V For Vendetta]

I've had my AMD x2 4200+ dual core cpu for a few month now and I'm happy with it but I don't think it's as good as many people say it is. Before I bought it there was all this hype that you can perform two tasks simultanously and you will not notice any slowdown. This is not true at least in my case, running two cpu intensive tasks at the same time does slow each other down quite considerably. For example extracting two movies at the same time from a RAR file does take longer that extracting them one at a time. How is everyone else finding their dual core cpus? Can you extract 2 very large RAR files simultanously without any slowdown?
I'm wondering if it's just me or are those cpus like that. I do have alll the latest driver and patches installed including the one from microsoft.

i might be wrong but most applications available now dont fully support dual cores

 

[Humate]

also, are you extracting the two rar files to different hard drives, from different hard drives?

 

[MeatLoaf]

I find this also, i was extracting a large file the other day and triied to extract another at the same time and it was slower than doing one at a time.

But, i can play games fine whilst encoding and stuff

 

[MadMatty]

In my case dual core has done the job I baught it for at thats to encode tv rips in real time. Not as fast as I thaught it should be (both cores dont seem to go higher then 70-80% usage), but plenty faster then my AthlonXP system

Average encoding times with AutoGK Xvid 350mb and a source file of 42 mins tv episode (usualy under a gig direct from freeview stream).

AXP 2500+ @3200 (2200) 1 hour 17mins
AX2 3800+ @4600 (2400) 42 mins

Not much change in games that ive noticed and multitasking hasnt really improved as much as i hoped it would though. Internet explorer is still sluggish if anything else is busy for instance.

 

[nikebee]

I find this also, i was extracting a large file the other day and triied to extract another at the same time and it was slower than doing one at a time.

But, i can play games fine whilst encoding and stuff

silly question, but you did remember to set the affinity of each process to different cores?

 

[Humate]

If you are extracting two rar files, the real test is having four identical drives, and extracting two rar files stored on different drives, to different drives.

 

[NathanE]

silly question, but you did remember to set the affinity of each process to different cores?

You weren't joking about that being a silly question

Affinity is only useful for fixing compatibility issues, usually with games. Apart from that it has no other meaningful purpose on the desktop.

 

[Day03]

I'll try extracting the files on different HDDs and see if it makes any difference. But it's not just extracting which is slow. Also when I use QuickPAR and then try to open the start menu it hangs for quite a while before opening.

 

[nikebee]

You weren't joking about that being a silly question

Affinity is only useful for fixing compatibility issues, usually with games. Apart from that it has no other meaningful purpose on the desktop.

i was under the impression that by assigning the task to a specific core it would run specifically under that core... how can that not be useful and serve no meaningful purpose?

i've seen plenty of people on here comment about it

edit:
extracting 2 large rar files using the 2 cores performing as one would cause slow down...

setting each process to be run on individual cores surely would run smoother?

 

[Digital Punk]

I've had a video encoding on one core and HL2 playing on the other at the same time on my Opty 170.

The only problem I had was some hard drive thrashing in HL2 as I only have 1GB of ram.

I was pretty impressed tbh.

 

[Psycho Sonny]

i was under the impression that by assigning the task to a specific core it would run specifically under that core... how can that not be useful and serve no meaningful purpose?

i've seen plenty of people on here comment about it

edit:
extracting 2 large rar files using the 2 cores performing as one would cause slow down...

setting each process to be run on individual cores surely would run smoother?

do you know how cpu's work? they can only work on 1 thing at a time but they switch so fast between the processes that it appears that they are doing everything 2gether, now lets just take 3 processes even though there will be 100 running at the same time just to simplify things, process 1 is the operating system, process 2 is dvd burning, process 3 is converting audio cd to mp3, lets say we have 2 cores, now 2 cores can switch between doing all 3 tasks therefore lets just say all 3 of them require equal power, the processor can only work on 2 of the 3 at the same time so it will switch between them and they will get 33% of the total power each, now we switch process 2 to core 0 and process 3 to core 1 but process 1 is still set to use both cores, now process 1 will get 50% usage and processes 2 and 3 will get 25% each because when they are switching about, process 1 can use either core but processes 2 and 3 can only use a specific core which may already be in use and have to wait in line

 

[dark4orz]

my sig tells it all !!

 

[FrankJH]

do you know how cpu's work? they can only work on 1 thing at a time but they switch so fast between the processes that it appears that they are doing everything 2gether, now lets just take 3 processes even though there will be 100 running at the same time just to simplify things, process 1 is the operating system, process 2 is dvd burning, process 3 is converting audio cd to mp3, lets say we have 2 cores, now 2 cores can switch between doing all 3 tasks therefore lets just say all 3 of them require equal power, the processor can only work on 2 of the 3 at the same time so it will switch between them and they will get 33% of the total power each, now we switch process 2 to core 0 and process 3 to core 1 but process 1 is still set to use both cores, now process 1 will get 50% usage and processes 2 and 3 will get 25% each because when they are switching about, process 1 can use either core but processes 2 and 3 can only use a specific core which may already be in use and have to wait in line

I think you got that last bit confuzed if you ask me!!!

process 1 has the potential to be working all the time (1/2 time on core 0 and 1/2 time on core 1) however when its on the opposite core the other process will take 100% of the cpu usage

so its really 100% and 50% / 50% ( process 1 would never be using both cores simultaneously, or highly unlikely)

 

[NathanE]

i was under the impression that by assigning the task to a specific core it would run specifically under that core... how can that not be useful and serve no meaningful purpose?

i've seen plenty of people on here comment about it

edit:
extracting 2 large rar files using the 2 cores performing as one would cause slow down...

setting each process to be run on individual cores surely would run smoother?

Windows load balances running threads across all available cores anyway. It certainly will not place two WinRAR extraction instances on the same core unless it has very good reason to do so. The issue with running two simultaneous archive extractions is not really CPU power but hard drive read and seek time. A SATA HD with NCQ can improve things for SMP systems a bit but apart from that, the HD will remain the bottleneck.

And like Psycho Sonny has said, a CPU's processing time is "split up" into what are called "time slices" or "quantums". These slices of processor time are then allocated to different threads. The allocation criteria changes almost by the second and includes such things as:

1. thread base priority
2. thread dynamic priority
3. whether some I/O (e.g. disk read) has just completed for that thread
4. whether a syncronisation object has just been signalled
5. whether the thread belongs to the process that is selected in the foreground

When a thread's quantum runs out, the kernel takes the thread away from the processor.

On a 'proper' dual core/multi core chip (e.g. an X2, Yonah or Conroe) there is pretty much zero overhead in switching a thread between cores anyway. Although the kernel will still try to avoid that situation (by remembering which processor/core the thread last executed on) so as to avoid a potential cache miss. But Vista will detect if the CPU has a shared L2 cache and in that case will remove that rule from its scheduling criteria. Obviously if you have a dual CPU box with two dual core processors installed then it will still need to use that rule now and then when it so happens that the thread's last core and its adjacent core are both tied up with a thread that has a higher priority.

 

[Stelly]

I dont know I have not got it yet

Stelly

 

[Admiral Huddy]

very interesting reading..
I'm very happy with my dual core. I use a piece of software i got from PC Gamer to assign certain applications to a specific core which is very usefull and for F@H it rocks..

 

[malachi]

Just like you Day03, I also own a Athlon 64 X2 4200+ and when trying to extract large files using Winrar, its quicker to do them one at a time. Even Windows takes longer to boot, my previous CPU (Athlon 64 3500+) the XP bar only moved twice accross the screen before going into Windows but now since the upgrade to dual core it moves about 6 times. But I can encode an 1hr 40mins divx movie to DVD just under 38mins using Windvd Creator 2 when before it took 1hr 10mins on my previous CPU and I can encode while playing COD2 without any slow downs which was near impossible before.

 

[Hawklord]

I went from an A64 3500+ to an X2 4200+ and didn't notice much difference playing games tbh. It did benefit from the fact that you can have more than one app running without it effecting games etc. Gernerally games offered the same performance as the single core.
I however managed to overclock the 4200+ to 2.75 ghz and that has given me a real boost in everything i tend to run
Get clocking your cpu's and unlock it's full potential then come on here and say it's not been a worhwhile upgrade

 

[kalniel]

What you should do is use a multi-threaded zip application, then rather than noticing you can do two tasks at once, you'll be able to do one task in half the time, and it really is a noticable improvement.

For more sciency stuff and other number crunching dual cores is a lovely thing. For playing games/office/web surfing? Nah, doubt I'd notice much difference.