Number of processors displayed?

[MysticColby]

So I just got my new baby yesterday: 6-core 3.33 Ghz Mac Pro with a SSD.
anyways, I downloaded iStat Menu, but there seemed to be too many CPU bar graphs (12 instead of 6 - every other one is blank). I checked Activity Monitor, and it has the same thing.
Though it would be awesome if Apple accidently sent me a 12-core Mac Pro by mistake, I've seen inside the box and that is definitely not that case.
Is this normal? It probably doesn't affect anything important; I'd just prefer it if iStat would take up less of my menu - I know I can squish them into 1 graph, but I'd prefer to have the individual CPUs there. Is there a way to correct this?
attached are screen shots of activity monitor CPU history and iStat CPU activity. I know they aren't very interesting graphs, but I'm not complaining
I just looked at that picture closer, and it looks like one of the ghost CPUs had some activity. I am at a loss of explanation.

thanks
-Colby

 

[spinnerlys]

Maybe it's the number of capable threads?
http://ark.intel.com/Product.aspx?id=47916

 

[dissolve]

The extras are virtual cores. I've got the quad and it displays 8. Every odd graph should be the real cores, while the evens are virtual.

 

[sammich]

Read up on hyperthreading.

Skinny: HT presents each physical core to your computer as two logical cores. Hence 2x as much in AM.

 

[MysticColby]

http://discussions.apple.com/thread.jspa?messageID=11511910 quote:

I discovered a way to do this a while back. In Leopard, there were two different ways to do this.
http://discussions.apple.com/message.jspa?messageID=9818633

Hopefully, this information is still relevant in Snow Leopard. And here's a breakdown:

Method 1:
CPUPalette - Library > Application Support > HWPrefs > CPUPalette

Method 2: (my preferred method)
Processor.prefPane - Developer > Extras > PreferencePanes > Processor.prefPane

the attached screen shot is of method 1. Pretty clear that that's what's going on. I'll try disabling Hyper-Threading and see if that clears the virtual CPUs
So disabling Hyper-Threading doesn't make the virtual CPUs go away (tried restarting, too, but it defaulted to yes Hyper-Threading).
suggestions? or do I just live with it?

 

[Transporteur]

So disabling Hyper-Threading doesn't make the virtual CPUs go away (tried restarting, too, but it defaulted to yes Hyper-Threading).
suggestions? or do I just live with it?

Disabling HT?
Why would you think Intel enabled it again? To make the machines slower?

HT gives you a performance boost of 10 - 15% depending on the applications you use.

 

[alphaod]

You can just have it show one graph with the menu icon and/or the history dropdown. Just switch it here:

Disabling HT?
Why would you think Intel enabled it again? To make the machines slower?

HT gives you a performance boost of 10 - 15% depending on the applications you use.

Well in the Pentium 4 days, HT did make the machines slower in some tasks.

So it is possible for the CPU to be slower with HT on, but less likely now that OS X is optimized for the technology.

 

[Transporteur]

Well in the Pentium 4 days, HT did make the machines slower in some tasks.

So it is possible for the CPU to be slower with HT on, but less likely now that OS X is optimized for the technology.

It has been tested long enough with the release of the Nehalem Pros in 2009 to say that HT should definitely stay enabled.
The system uses all physical cores before the virtual ones, which is why people don't see the virtual core meters to crank up before they run tasks that can utilise more threads than physical cores are available.

 

[strausd]

Disabling HT?
Why would you think Intel enabled it again? To make the machines slower?

HT gives you a performance boost of 10 - 15% depending on the applications you use.

It is actually more like 30%.

 

[goMac]

Well in the Pentium 4 days, HT did make the machines slower in some tasks.

Not really. My P4 wiped the floor with my dorm mate's machines back in the day, and the only reason it did was HyperThreading. Turn Hyperthreading off, and the Athlon machines on the floor would outrun my tower...

 

[Transporteur]

It is actually more like 30%.

30%?
Doubtful. Where did you get that information?

 

[300D]

Its very application and situation specific. HT only uses portions of the CPU not being used by other processes.

 

[seek3r]

Not really. My P4 wiped the floor with my dorm mate's machines back in the day, and the only reason it did was HyperThreading. Turn Hyperthreading off, and the Athlon machines on the floor would outrun my tower...

Depends on what you're doing. Then, as now, if I peg all the cores in a machine to run, say, a DOCK job, hyper threading can slow things down.