I have machines (all desktops) with your same OS but the I7-950. This is the same CPU and the only the difference is in the base clock frequency (and price unfortunately). I have them run at about 3.6 GHz. They are all connected to internet either through a home wireless lan or through ethernet cable. I have a high bandwith main internet connection on coax cable from a cable operator.
For the machines devoted to WCG 24/24 I use the prefs with 1.0 day additional work and with the Activity Tab set as:
Run always and Network activity always available.
For the machines that are also for work or personal use I have the local preference set to : Only after computer has been idle for 1 minute. I have one also set to While computer is in use. I set to Connect every = 0.00 as this means continuous connection.
So I have some variety of configurations here but never had problems other than too many errors from some devices on HPFP2. But this problem has never been understood. Over time the percentage of errors becomes acceptable. Anyway you have no CPU time or points loss, so it is acceptable.
I know that the Security softwares, firewalls and antivirus can generate trouble. I use the Kaperski Internet security 2010 full pack on all my devices and had no problem with the Boinc software.