Extremely slow internet speed on 10.10.4 (14E36b)

Hello,

My MBP has been pretty much unusable for internet browsing since updating to this beta. I've tried a multitude of "fixes" many of which or well known such as deleting certain files within /Library/Preferences/SystemConfiguration then restarting to rebuild the .plist. I've also tried a couple of fixes involving bluetooth and also used namebench to find the best DNS.

I'm also running this build on my iMac and that's absolutely fine so it must be something to do with my machine.

Is anyone else experiencing this and if so have you found a solution?

Thanks