Boinc detects more CPUs than are present.
25 Sep 2010 21:22:56 UTC
Topic 195345
(moderation:
I'm running Boinc on a 3Ghz Pentium 4 Machine and it detects my machine as having 2 cores when it actually only has 1. Is there any way to fix this? I've tried doing CPU Benchmarks again, hoping that it'd pick up on the mistake, but it didn't.
Boinc detects more CPUs than are present.
)
Your Pentium 4 does something called Hyper-threading, where besides the actual processor, you also have a virtual processor.
So BOINC isn't wrong when it sees two processors (not cores).
You can disable hyper-threading in your system's BIOS (requires a restart of the computer and possibly a reinstall of Windows), or you can tell BOINC to only use 50% of the processors, in the Computing preferences: On multiprocessors, use at most 50% of the processors (Enforced by BOINC 6.1.0+).
Hi! Chances are that your
)
Hi!
Chances are that your Pentium 4 supports a technology called "Hyperthreading" and that it's currently enabled in the BIOS setting of the PC:
Hyperthtreading is used to boost the efficiency of the CPU by allowing more programs to run simultaneously than there are physical cores. To do this, basically the CPU will appear as a dual-core to the operating system: it's faking 2 "virtual" cores where there is only one.
In most situations this is a good thing, and you probably don't want to disable this globally for your PC (you could do that in the BIOS settings). With Hyperthreading enabled, a Pentium 4 will execute two threads a bit slower than actually running one of the threads alone, but not half as fast. So overall you get a performance boost because more computations will be done at the same time.
http://en.wikipedia.org/wiki/Hyper-threading
If you still would like to limit BOINC on this particular host to use one one virtual core (so basically using "half the physical CPU" only...kind of), you can do so in the Preferences settings of BOINC manager (in advanced view): near the bottom of the dialog (first tab), you can choose to use only a certain percentage of available cores.
So in your case, 50% would tell BOINC manager to have only one BOINC app running at the same time even tho the Pentium 4 could execute 2 in parallel.
Happy crunching
HB
EDIT: Jord beat me to it :-)
Thanks!
)
Thanks!