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CPU Cores not displaying properly - Windows 8 x64

My machine has 4 cores and 8 logical cores.  Device Manager correctly reports 4 cores.  Task manager shows 1 core and 2 logical cores.  I already updated BIOS.  How to fix?  

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David Johnson, CD
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Intel speedstep may have disabled cores that are not active.
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In an attempt to decrease overheating, at some point I had disabled that and some other performance settings in BIOS.  Turned those back on, and now I see all my cores.

The overheating problem is back, but I suppose I will actually need to take care of that issue now...
Hold on thar, Nelly...

I went into BIOS and defaulted it to the Failsafe settings and turned up the fans to full speed.  That also unleashed the 2nd CPU I had previously switched off and kept in reserve.  Now when I look at Task Manager, it is STILL reporting incorrectly.  Device Manager correctly shows my 16 logical cores.

So, it looks like the solution was actually not the solution...

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Looks like a bug to me, it should show

Sockets : 1
Cores: 4
Threads : 8

as per

I suspect it's a bug in Task Manager, because there are already Bugs reports, such as Ram reports as DDR2, when it's DDR3!

if you select Change View to Logical Processors, do you get 2 or 8?

Based on a Single CPU processor installed and active. (double it it both active)
Silly question Wich OS are you using?
Thank you for the posts.

"If you select Change View to Logical Processors, do you get 2 or 8?": 2 graphs show

It is running the fantabulous [sarcasm] Windows 8 Enterprise edition.  Fully patched.

Additional:  When I run processor intensive software or processes, it really does only use the 2 logical processors.  They completely max out at 100% utilization whereas it should barely be breaking a sweat if all 8 (a single CPU) or 16 (both CPUs) were being utilized.
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Andrew Hancock (VMware vExpert PRO / EE Fellow/British Beekeeper)
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"Was multi processors turned off, when you installed? "

I do recall multiprocessors were turned on when I installed.  I do recall seeing 16 logical processors showing in Task Manager.

I fiddled a bit with BIOS settings and such as I tested and learned the new system, but I set those back to default settings since.  The motherboard is a X8DAL-i.  I upgraded the BIOS using BIOS vR2.1 - X8DAL31.C30.  I reset to default settings afterward.  It has two default settings: one for optimal performance and another setting for redundancy.  Same results using either setting.

I recently (yesterday) confirmed one of the three DIMM channels is no longer working on the mobo.  There might also be a problem with CPU1, but I haven't confirmed it completely.  As it is at the moment, I pulled CPU1 out and it is running on CPU2 and with two 16 GB DIMMS in channel 0 and 2.  Channel 1 doesn't work having tested working DIMMs in it.  Task Manager still hasn't changed other than now showing 32 GB RAM.  Device Manager shows 8 logical.  Task manager shows 2 logical.

Thanks for continuing to help me probe this problem.  I am planning to RMA the mobo soon, but I still think Task Manager should be reporting what is showing in Device Manager.

I do not think it matters, but I will throw it out there anyway:  The only time I recall doing anything like explicitly setting CPUs to 2 was when I was configuring a fresh Windows Server 2013 test VMware v9.0 machine.  In that vm, I explicitly set CPUs available to 2.  I discovered the Task Manager issue after that, but I cannot say it was because of that.  I would doubt it, but there it is for anyone who may know better than I...
I've been seeing alsorts off issues with Task Manager, I've had it stating DDR2, when DDR3 memory in use, and now DDR2/DDR3 has disappeared, since changing the memory to faster DDR3!

Check with CPU-Z. does it report cores, cpus correctly, and Coreinfo
Per that link, there is at least one other person complaining about the same problem.  I'll just chalk it up to the great product MSFT delivered [sarcasm] and await a patch.
Thanks. I've been having some very weird Task Manager related issues today, fully utilised Memory, e.g. 48GB, Task Manager showing 98%/100%, but only 1.5GB used!

Resource Manager and other tools reports 48GB in use!

So, I went into msconfig and discovered CPU was checked and set at 2.  I unchecked it, rebooted, and HOLA!  All 16 of my logical processors were cranked up in their fully glory.  I got all teary-eyed.  I missed them so...

I suppose somewhere along the line, probably when I performed a system restore, that box was re-checked.
That's good, I've also seen it does not report speed correctly, it only reports the stock speed, and not the current speed!