Supernode - In peer-to-peer networking, a supernode works as one of that network’s relayers and proxy servers, handling data flow and connections for other users. This usually requires a fairly fast Internet connection with a lot of bandwidth and a modest amount of CPU time, as a lot of data will invariably pass through the supernode and needs to be processed.

Some peer-to-peer designs allow for the user to choose whether they ever want to be treated as supernodes; others do not. Skype by default is configured as a supernode, an issue that has caused controversy.

В двух словах и по-русски - Skype имеет особенность жрать как трафик, так и оперативку, причем особенность эта по умолчанию.

There are several ways to prevent Skype from becoming a supernode:

* Beginning with Skype 3.0, an explicit switch is provided in the registry settings to allow the disabling of supernode functionality.
* Any computer hosted on a network that is behind a network address translation (NAT) device or restrictive firewall will disable supernode functionality.
* Skype clients behind an HTTP or SOCKS5 proxy will not serve as supernodes.

http://www.skype.com/security/universities/

Save and run the following text as NoSuperNode.reg (a reboot will be requred):

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Skype]
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Skype\Phone]
“DisableSupernode”=dword:00000001

https://www.cs.uwaterloo.ca/twiki/view/CF/SkypeConfiguration#Disable_Supernode