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Old 02-06-2012, 10:42 PM   #1
masterchef341
 
 
 
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Lightbulb Clarification on how much CPU steam is actually using when idle.

First off, yes, steam is using too much CPU when idle. Now that that's out of the way, let's move on.

How much CPU is steam actually using? If you're on a quad core mac, you may look at activity monitor, see the report of 25%, and start panicking because it's apparently maxing out an entire core, or taking up 1/4 of your total processing power.

However, this is not right. Here's how activity monitor works:

In the lower left, %User, %System, and %Idle describe how much of your overall processing power is being used by applications like steam, by the operating system, and how much is idle. This section reads the same (out of 100%) no matter how many cores you have.

However, in the main section, where you can see process IDs, names, and % CPU, things are being reported differently. If you have a single core mac, % CPU is out of 100%. If you have a dual core mac, it's out of 200%. If you have a quad core, it's out of 400%, etc.

So, if you're running a quad core mac and activity monitor is reporting steam at 25%, it's actually just using 25% of one of your cores. If you're running a dual core mac, activity monitor is still going to report about 25%, because it's still using 25% of one of your cores.

This might be obvious to some people, but there are enough people confused about this to warrant an explanation.

Here's hoping valve gets around to reducing this down to some marginal amount, but I have do have one comment on the matter. When (good) professionals write code, the highest priorities are to generate code that is manageable, readable, maintainable, and accurate. Performance is not anywhere near the top of the list. That's just the nature of software development. It's definitely about time for valve to fix the CPU bug, but overall I'm actually happy that steam is at least operating pretty smoothly, and that they made it this far.
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Old 02-07-2012, 01:45 PM   #2
Minamimoto Sho
 
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Quote:
So, if you're running a quad core mac and activity monitor is reporting steam at 25%, it's actually just using 25% of one of your cores. If you're running a dual core mac, activity monitor is still going to report about 25%, because it's still using 25% of one of your cores.
Doesn't the percentage indicate the CPU time being used out of the rated clock speed?

http://en.wikipedia.org/wiki/Hertz

Just saiyan.

Last edited by Minamimoto Sho: 02-07-2012 at 01:49 PM.
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Old 02-07-2012, 04:15 PM   #3
Earthling84
 
 
 
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When I run a torture test with Prime95, Activity Monitor says that it's using ~746% CPU. So OP is right.

Last edited by Earthling84: 02-08-2012 at 03:05 PM.
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Old 02-07-2012, 04:57 PM   #4
MarcBook
 
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Yes, this is all well and true, but it's still a significant enough amount of CPU power being used to make my Mac (and many others', mostly notebooks) have to increase the fan speed quite a bit to a noticeable level.

This symptom is pretty irritating in a quiet room and prevents me from leaving Steam open in the background, which I'd like to do sometimes during my free time.

I agree, however, that the issue isn't as bad as some might think, but it's still a pretty bad problem with the Mac client.
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Old 02-08-2012, 12:26 AM   #5
masterchef341
 
 
 
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Originally Posted by MarcBook View Post
Yes, this is all well and true, but it's still a significant enough amount of CPU power being used to make my Mac (and many others', mostly notebooks) have to increase the fan speed quite a bit to a noticeable level.

This symptom is pretty irritating in a quiet room and prevents me from leaving Steam open in the background, which I'd like to do sometimes during my free time.

I agree, however, that the issue isn't as bad as some might think, but it's still a pretty bad problem with the Mac client.
duly noted.
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Old 02-08-2012, 09:00 AM   #6
apdonato
 
 
 
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cool beans
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Old 02-08-2012, 09:05 AM   #7
apdonato
 
 
 
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Originally Posted by Earthling84 View Post
When I run a torture test with Prime95, Activity Monitor says that it's using ~746% CPU. (I have an i7 processor.) So OP is right.
umm... yeah 746% cpu has nothing to do with having an i7 processor...

i7 processors range in number of cores.
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Old 02-08-2012, 09:12 AM   #8
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Sorry masterchef341, but your explanation is wrong. It doesn't matter if it is a single, dual or quad core processor, it depends how many threads it can use. The dual core sandy-bridge processors mostly use 4 threads while the quad cores have 8 threads. So if you have one of these, Steam uses 25% of a total 400% or 800%. Still too much as every idle application should use <1%.
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Old 02-08-2012, 09:16 AM   #9
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Originally Posted by Skoopman View Post
Sorry masterchef341, but your explanation is wrong. It doesn't matter if it is a single, dual or quad core processor, it depends how many threads it can use. The dual core sandy-bridge processors mostly use 4 threads while the quad cores have 8 threads. So if you have one of these, Steam uses 25% of a total 400% or 800%. Still too much as every idle application should use <1%.
You just blew my mind...
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Old 02-08-2012, 11:22 AM   #10
Earthling84
 
 
 
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Originally Posted by apdonato View Post
umm... yeah 746% cpu has nothing to do with having an i7 processor...

i7 processors range in number of cores.
Oops, sorry. For some reason I had just assumed they were all quad-core with hyperthreading. Nevermind.
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Old 02-08-2012, 03:40 PM   #11
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Originally Posted by Earthling84 View Post
Oops, sorry. For some reason I had just assumed they were all quad-core with hyperthreading. Nevermind.
Most are, but not all. I have a quad core i7 as well but I've read an article about how it depends... oh wait, here it is:

http://www.pcworld.idg.com.au/articl...ore_i3_i5_i7_/

Well, now that I have re-read the article, maybe they are all quad cores... idk ...It isn't very clear.

Last edited by apdonato: 02-08-2012 at 03:46 PM.
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Old 02-08-2012, 05:48 PM   #12
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Originally Posted by masterchef341 View Post

How much CPU is steam actually using? If you're on a quad core mac, you may look at activity monitor, see the report of 25%, and start panicking because it's apparently maxing out an entire core, or taking up 1/4 of your total processing power.

However, this is not right.
Thanks for spreading the word on this. When I posted on the cpu thread about this, I didn't realize how many people thought steam was using up a whole core of their CPU! The client is inefficient, but it's not that bad!
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