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One core on Intel Core 2 Duo not working

peteus

New Member
Joined
Aug 12, 2007
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Processor Intel C2D E6420
Motherboard ASUS P5B Deluxe P965 775
Cooling Air, CPU Cooler Scythe SCMN-1100 RTL
Memory G-Skill, 4x1GB
Video Card(s) Gigabyte GeForce 8400 GS
Storage 2x WD5000AAKS Western Digital 500GB
Case Antec
Power Supply Antec
I've just put together a new computer and one of the cores of my dual core CPU is not working!

This is what I have:

Motherboard: ASUS P5B Deluxe (P965 chipset)
Processor: Intel Core 2 Duo E6420 2.13 GHz
OS: Windows Vista Ultimate 32-bit

BIOS shows "Count 2" for the number of processors
BIOS does not support turning on/off one of the cores

My Computer --> Properties shows:
Intel(R) Core(TM)2 CPU 6420 @ 2.13GHz 2.13 GHz

Device Manager shows 2 processors, both "working properly".

So far so good ...

Now, the problem:

The Task Manager in the Performance tab shows only one Processor/Core--see attachement).

I installed Multi Meter(D) (a gadget for Windows Sidebar) that shows the load on each core separately--the second core is always at 0 (even if the first is at 100%)--see 2nd attachement.

In the task manager, there are jobs that sometimes run at 90% or so CPU.

I've tried to install Intel's INF files "http://downloadcenter.intel.com/Detail_Desc.aspx?agr=N&ProductID=2529&DwnldID=13499&strOSs=156&OSFullName=Windows%20Vista*%20Ultimate,%2032-bit%20version&lang=eng" but that did not make any difference.

Both MB and the CPU are still under 30 day replacement warranty from newegg (for another 3-4 days) but I am not even sure which one if any is defective.

I'd very much appreciate any ideas on how to fix this or how to figure out which of the MB or CPU is broken.
 

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Looks much more like a windows issue... Did you reinstall windows?
 
its a windows issue. in device manager, you'll have something under 'computer' (not processors)

I'm in vista, and its different but its something like "ACPI uniprocessor PC" or "ACPI multiprocessor PC"

you just gotta uninstall that one and get it to use the multi, not single - most often caused by using an old windows install.

For reference: i'm damned tired atm, any other members who notice a mistake with what i said, please correct me. Pretty sure i had the steps right to fix it tho.



Oh and also, update the bios on the mobo. its possible the shipping bios doesnt support the newer revision core 2 duos (those that end in 20,50 etc)
 
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Get Speedfan, run Orthos with Small FFT's and Priority 9, you will see either both bars loaded in Speedfan or one bar. That will prove whether nor not both cores are working. Like the others said it sounds like a windows issue, though one I've never had. Hope that helps! :toast:
 
Have not tried yet, thanks for the suggestion!
 
Get Speedfan, run Orthos with Small FFT's and Priority 9, you will see either both bars loaded in Speedfan or one bar. That will prove whether nor not both cores are working. Like the others said it sounds like a windows issue, though one I've never had. Hope that helps! :toast:

kursah: those programs tap into windows performance graphs and use those, since it doesnt show in task manager, it wont show in those programs either.

His info suggests the hardware is installed correctly, but the OS is set to run as if it had a single core, and ignoring the second one.
 
Hmm, interesting, well since I've not had this problem ever, I wouldn't know. Thanks for the info Mussels. I recommend he still try it to verify, unless you have before, it may be worth a shot just to make sure. That's what I've done to prove to people both cores are working before and what I do when stressing my cores. I hope it works for him and I also hope both cores are working and that it's just a simple windows glitch. :toast:
 
u have got service pack 2 , right?
 
its a windows issue. in device manager, you'll have something under 'computer' (not processors)

I'm in vista, and its different but its something like "ACPI uniprocessor PC" or "ACPI multiprocessor PC"

you just gotta uninstall that one and get it to use the multi, not single - most often caused by using an old windows install.

For reference: i'm damned tired atm, any other members who notice a mistake with what i said, please correct me. Pretty sure i had the steps right to fix it tho.



Oh and also, update the bios on the mobo. its possible the shipping bios doesnt support the newer revision core 2 duos (those that end in 20,50 etc)


In device manager, there's only "Advanced Configuration and Power Interface (ACPI) PC". I did not see anything about multi or single. Also there was no way to uninstall the driver. When I asked windows to look for updated driver on my PC or the Internet, "Windows has determined the driver software is up to date" and "the best driver software for my device is already installed".

Any ideas how to uninstall the ACPI driver and where to get more up-to-date one?
 
Did you try Speedfan just to verify? Did it show up only one core?

You may need to change a setting or two in bios for ACPI 2.0 etc. I never did for dual core detection, but that may be an issue.

Also, you should fill out your System Specs in User CP, it will be more helpful for those catching up with the situation. :toast:
 
In device manager, there's only "Advanced Configuration and Power Interface (ACPI) PC". I did not see anything about multi or single. Also there was no way to uninstall the driver. When I asked windows to look for updated driver on my PC or the Internet, "Windows has determined the driver software is up to date" and "the best driver software for my device is already installed".

Any ideas how to uninstall the ACPI driver and where to get more up-to-date one?

You may have to reinstall or just maybe attempt to select one to use... Not sure on that one.
 
Get Speedfan, run Orthos with Small FFT's and Priority 9, you will see either both bars loaded in Speedfan or one bar. That will prove whether nor not both cores are working. Like the others said it sounds like a windows issue, though one I've never had. Hope that helps! :toast:

Thansk for the suggestion. I ran Orthos, one of the lines in the log said: Using CPU #0.

CPU was at 100% on Speedfan, Core1 was at 100% on Multi Meter, Core2 was at 0.

I am not sure which 2 bars you were talking about, there's only one in Speedfan.

As Mussels was saying, this seems to be a Windows ignoring the second core.

And yes, I have updated the BIOS from ASUS website, just forgot to mention it.
 
If one core wasnt functioning... I wouldnt see how the processor would function with one core anyway. The ROM wouldn't like it :p.

Still this is a very odd issue, I wouldnt worry too much about it though, and as they asked, are you using SP1 or SP2? (Not that it would matter but hey!). Try a FULL reinstall of windows though.
 
If one core wasnt functioning... I wouldnt see how the processor would function with one core anyway. The ROM wouldn't like it :p.

Still this is a very odd issue, I wouldnt worry too much about it though, and as they asked, are you using SP1 or SP2? (Not that it would matter but hey!). Try a FULL reinstall of windows though.

This is Vista, no SPs yet :)

I am trying to avoid full re-install but I guess I'll have to do it sooner or later :twitch:
 
So no one noticed he's on Vista then?

My dad had this problem in XP because he didn't uninstall his 3500 before installing his X2 4200. Wouldn't use the second core, had to reinstall in the end.

What you can try is going in to Device Manager, and finding the option to show all hidden devices, it may bring up your old CPU, uninstall it and restart. If that doesn't work then you could try downloading Intel drivers (assuming there is a Vista compatible version, and they exist).

If none of that works then I'm afraid it looks like a reinstall is needed.
 
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So no one noticed he's on Vista then?

My dad had this problem in XP because he didn't uninstall his 3500 before installing his X2 4200. Wouldn't use the second core, had to reinstall in the end.

What you can try is going in to Device Manager, and finding the option to show all hidden devices, it may bring up your old CPU, uninstall it and restart. If that doesn't work then you could try downloading the AMD drivers (assuming there is a Vista compatible version).

If none of that works then I'm afraid it looks like a reinstall is needed.

He's got a Intel Core2 6420 though, how would AMD drivers work? LoL! :toast:

I do agree with the Windows Re-install though.
 
Lol sorry, reading 2 posts at the same time :P The other guy's got an X2 5200....

I guess we are ALL guilty of not reading things properly :P
 
Lol sorry, reading 2 posts at the same time :P The other guy's got an X2 5200....

I guess we are ALL guilty of not reading things properly :P

Damn right! I'm sure you found one of mine, I did the same, but it ended up being really funny to a lot of TPU users! LoL! Hey we can help till we go cross-eyed! There's always gotta be room for mistake and for others to step in and help. Didn't mean to offend ya dude, just thought I'd point it out! If I did offend ya, I'm sorry man! It's all in good fun!

:toast:

TPU FTW!
 
Damn right! I'm sure you found one of mine, I did the same, but it ended up being really funny to a lot of TPU users! LoL! Hey we can help till we go cross-eyed! There's always gotta be room for mistake and for others to step in and help. Didn't mean to offend ya dude, just thought I'd point it out! If I did offend ya, I'm sorry man! It's all in good fun!

:toast:

TPU FTW!

Haha, no offence taken man :laugh:
 
In device manager, there's only "Advanced Configuration and Power Interface (ACPI) PC". I did not see anything about multi or single. Also there was no way to uninstall the driver. When I asked windows to look for updated driver on my PC or the Internet, "Windows has determined the driver software is up to date" and "the best driver software for my device is already installed".

Any ideas how to uninstall the ACPI driver and where to get more up-to-date one?

thats the one. you can right click it and update the driver, and choose ACPI multi-processor, its worded like that. Dont do it automatically, or look online - its AUTOMATICALLY chosen the wrong one, you see...


Just to update: my thinking was on XP, i did say i was tired - i'll see what it says in my vista PC's.

Ok on the vista PC's it doesnt appear so simple, they all say its an "ACPI x64-based PC" (or x86 on the netbox)

You probably will need to format and reinstall, to make it work.
 
Hmm lemme try to uninstall the x64 acpi on device manager lol, experimental vista installation here.... brb gonna save a restore point and uninstall it.... post back later
 
I am re-installing Vista now ... Wish me luck ;):)
 
I am re-installing Vista now ... Wish me luck ;):)

All's well that ends well! My machine is working correctly now!

The solution was
(a) Enable ACPI 2.0 Support in the BIOS (suggested by Kursah--THANKS!!! :toast:)
(b) Re-install Vista (suggested pretty much by everyone :))

Thank you all for your valuable input! Now I am a happy man!
 
ACPI 2.0 should have beeen on by default? oh well.

and congrats on getting it working, core 2 duo/quads are just so damned good.

I've had my quad 3 days now, and at 2.4GHz its as smooth (for gaming/multitasking) as my E6600 was at 3.4... its just bliss compared to my AM2 netbox *glare*
 
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