Windows 7 Missing Cores


New Member
I have searched through this forum without much luck on this subject.
I have a Intel quad core Q6600 CPU but only 2 of the cores are showing up in the Task Manager but if
I check the device manager all 4 are showing there.
Does anyone know if Windows 7 is using all 4 cores and just not showing 2 of them or just using 2 of them?
Also only 2 show up if I check MSconfig.
All 4 showed up Task Manager under Vista.


New Member
This is an odd problem Beaker... I'm not sure right off the top of my head why that would be unless it has something to do with the fact that Windows 7 shuts down cores when there not in use to conserve power... That would be the only thing I could think that it might be... ;) I'll do some more research for ya though and see if I can find anything else out.. I'll report back if I find something.. :)


New Member
Hi there
Mine reports
Processor Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHZ 2.67 GHZ
Memory (RAM) 8.00 GB
System Type 64 Bit operating system
(I'm using W7 X-64 build 7000)

Looking at the device manager I see under Processors 4 entries as per below
Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHZ .

From the Task manager (works slightly different in W7 than Vista). Under CPU click Resource Monitor . On Performance click resource Monitor then unlike Vista you get some tabs. Choose CPU. Then on the right hand side of the screen I get 6 boxes with a graph in them
CPU Total,
Service CPU Usage
Cpu 0.
Cpu 1.
Cpu 2.
Cpu 3.

On Vista you just get 4 individual Boxes on performance across the top of the screen.

Don't seem to have any problem with this.

Strangely enough when I try and use the Intel CPU identification utility (download from Intel site) I get Your Processor was released after this version of the utility became available - unavailable to provide details !!!!

The Processor box clearly says INTEL Q9400 !!

Maybe your Mobo only supports a Dual core
I'm using an ASUS P5QL-CM .



New Member
It's a brand new motherboard.
A Gigabyte S-Series GA-EP45-DS3R/DS3 and it does support quad core CPU's.Checked on the web site.

IntelCoreâ„¢ 2 Quad Q6600 2.40HGz 8MB Kentsfield 65nm G0 95W 1066 F5

As I mentioned in my first post "All 4 showed up under Vista".


New Member
Yes it's set to view each CPU.
I am almost sure that when I first installed W7 and I was mooching around the sytem that
all 4 cores where visable and working in Task Manager and it was only the other night
that I noticed that 2 of the cores had gone.


New Member
Try a multiple movie conversion task.
Try to use a converter (Like Xilisoft's HD Converter) that supports multiple cores. If it runs all 4 conversions simultaneously, then they're all recognized.


New Member
Hi there -- this might be a red herring but could possibly this feature be required to show all 4 CPU's

For my Mobo (ASUS P5Ql-CM) the documentation has this snippet over 45nm technology.

LGA775 Intel® 45nm Processor Ready
This motherboard supports the latest Intel 45nm CPU which introduces new micro-architecture features for greater performance at a given frequency, up to 50% larger L2 caches, and expanded power management capabilities for new levels of energy efficiency.

The Q9400 Quad is one of these CPU's using the 45nm technology.
Whether this stuff is needed to show the 4 cores I haven't a clue but it sometimes is a help when looking at 2 computers running the same OS with different results to check and see what the differences are.

Now I'm not a physicist but that's the only difference I can see possibly as why 2 or 4 cores would show. I m just watching a DVD on the Win 7 box with the QUAD processor - bog standard DVD (Win DVD 8) no blu ray one , nothing else running (or at least no user applications) and it clearly shows all 4 cores in the task manager. I'm on the Net on a Different computer so the other machine just running Task Manager and Win DVD 8.



New Member
45nm "technology" has to do with the size of the processor die.
It has nothing to do with actual features, it's just a manufacturing process.
There is no way that it could possibly have anything to do with the cores registering with the OS.


New Member
Have you checked in the BIOS to see if all of the Cores are enabled? Something might have disabled two of them.