Windows 7 won't use all my CPU's cores

My computer (HP xw6600 Workstation) has two Intel Xeon processors which have 8 cores each, but system manager and performance manager only see four cores.

The Device Manager shows eight Intel(R) Xeon(R) CPU E5410 @ 2.33GHz. They are all installed and drivers working perfectly but still only four cores are in use.

How can I get Windows to use all the cores?

System specs:

HP xw6600 Workstation
CPU: Two - Intel Xeon E5410 @ 2.33GHz
HDD: WD 500GB Sata Drive
RAM: 4GB

user256389

Posted 2013-09-22T07:45:49.640

Reputation: 9

As per.manufacture specs it only has 4 cores http://ark.intel.com/m/products/33080/#@product/specifications

– 50-3 – 2013-09-22T07:59:09.817

Also it's good practice to include which version of windows you're using – 50-3 – 2013-09-22T08:05:03.470

@50-3 he said there's 2 of 'em! And check the title. – Neil Neyman – 2013-09-22T08:05:19.790

@Neil "two intel Xeon possessors each with 8 cores" – 50-3 – 2013-09-22T08:06:42.930

@50-3 misread that. I wonder if he meant it the way I read it becAuse otherwise he'd be expecting 16 cores. – Neil Neyman – 2013-09-22T08:10:25.423

@neil as per his device manager output all looks normal so unless he can give clear information it's going to be hard to answer, also if your suspicion is correct he might not have installed a compatible version of 64 bit for dual CPU – 50-3 – 2013-09-22T08:13:43.167

Answers

Might be core parking you are seeing. Basically the os decides it doesn't really need all 8 at the moment and shuts some down to save power. The link I provided has some ways to turn this off if you want, but from what I understand in theory it only does this when it determines there's no performance benefit to be gained from the extra cores.

Reminds me of a modern dodge hemi v8 5.7 with a feature called MDS which goes into 4 cylinder mode while maintaining speed on the highway for better fuel economy. But as soon as you accelerate again its back on all 8.

Neil Neyman

Posted 2013-09-22T07:45:49.640

Reputation: 246

Nice link and good answer but he hasn't said he can't see both CPU just he can only see 4 CPU cores, he has provided very little details but I like your answer – 50-3 – 2013-09-22T08:10:33.667

He said device manager shows all 8 with only 4 graphs running. Or at least that's how I interpreted it! – Neil Neyman – 2013-09-22T08:11:23.990

Windows 7 Home Premium and Home Basic are limited to one physical processor. To use two physical processors, you will need to run at least Windows 7 Professional. As you didn't mention the edition of Windows you're running, that might be the problem.

See Windows 7 system requirements.

Gene

Posted 2013-09-22T07:45:49.640

Reputation: 1 403