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
  • As per.manufacture specs it only has 4 cores ark.intel.com/m/products/33080/#@product/specifications – 50-3 Sep 22 '13 at 7:59
  • Also it's good practice to include which version of windows you're using – 50-3 Sep 22 '13 at 8:05
  • @50-3 he said there's 2 of 'em! And check the title. – Neil Neyman Sep 22 '13 at 8:05
  • @Neil "two intel Xeon possessors each with 8 cores" – 50-3 Sep 22 '13 at 8:06
  • @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 Sep 22 '13 at 8:10

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.

  • 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 Sep 22 '13 at 8:10
  • He said device manager shows all 8 with only 4 graphs running. Or at least that's how I interpreted it! – Neil Neyman Sep 22 '13 at 8:11

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.

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