I have not experienced this in the slightest. In fact, my OS X (always on the latest, and am now on 10.10.4) is completely stable. There might be an app or two crashing now and then, but that's not on OS X's shoulders, rather the apps themselves. I think the only issue I had was that one of my universities WiFi's became unstable, but more factors might play in since they use a lot of custom configurations for security on that one.
I'm rather interested in what might be causing what OP describes? Since it doesn't just affect the owners PC, it must be transmitting something over the network. Could this perhaps be from an application instead, that might have been affected by internal changes due to the update (someone mentioned the Photo app)?
I'm rather interested in what might be causing what OP describes? Since it doesn't just affect the owners PC, it must be transmitting something over the network. Could this perhaps be from an application instead, that might have been affected by internal changes due to the update (someone mentioned the Photo app)?