I've two machines with SQL Server 2012 Express SP1 with default configuration settings for CPU usage.

I'm using this query on my work machine:

SELECT cpu_count
FROM sys.dm_os_sys_info

It returns "4", which is true.

The same query on production machine returns "1" (that machine has 4 processors too). There's no additional CPU usage settings in both cases, except defaults.

Production machine is a virtual machine, which, possibly, was reconfigured after SQL Server installation.

Is there any way to reconfigure SQL Server for using of 4 processors?

1 Answer 1


SQL Server Express is limited to 1 CPU only

(to add more details it's limited to one socket or four cores, whichever is less)

see http://msdn.microsoft.com/en-ie/library/cc645993.aspx

  • Depends on what you mean by "CPU". The actual restriction is "Limited to lesser of 1 Socket or 4 cores" Apr 2, 2013 at 14:07
  • Do you mean physical CPU or cores?
    – Dennis
    Apr 2, 2013 at 14:09
  • @EdHarper: thanks for the link, I think, the problem is that on my work machine I have 1 CPU with 4 cores, and on production - 4 CPUs.
    – Dennis
    Apr 2, 2013 at 14:11
  • It is worth adding that you may be able to configure your hypervisor to present a single socket to your server, but with multiple cores. More details here: serverfault.com/questions/385079/… and also here serverfault.com/questions/422805/…
    – RoKa
    Apr 2, 2013 at 15:56

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