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I've found a common subject in forums asking about using VPNs to reduce latencies between the gamers and the game servers. I've even found some blog posts confirming this.
From my understanding, using a VPN shouldn't reduce latency at all, unless routers somehow treat encrypted packets differently.
What's the truth here? Does the type of VPN make a difference?
SUMMARY OF COMMENTS/ANSWERS: While in the ideal net neutral world latency over a VPN should be greater or equal to latency over a public network, in the real world with crappy ISPs latency could actually be reduced by using a VPN. Pity! Especially because it leads to a "try it an see" approach on each particular ISP.
Unless we are talking about something like ISP provided VPNs (MPLS or similar) that can have a different routing and priority characteristics. But if you get one of these you are usually aware and paying for it. Not very likely in casual gaming scenarios.