You might also need to check your network configuration. Sometimes firewall and router settings get in the way. This also means that settings which work one way may not always work the other way in network directionality.

Of course if I'm confused a little and you're just talking about one computer rather than connecting the two of them... There should be a tick box lower down under render settings that says "multi-threaded" that needs to be checked on. The render settings panel does scroll, depending on screen size.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.