Using a brand name slocket can have a big impact on overclocking potential and voltage.
For example: I had a MSI slocket on my Cel. 366@550 running @ 2.1v when I got another processor. So I swapped the MSI out to use on the new CPU for a generic no-name slocket. With the generic slocket, the processor would not run stable @550 @ 2.1v => it required a bump to 2.2v to now run stable.
I think I speak for most everyone when I say the slocket does make a difference.