iChat Unusable After Recent OS Update.

I'm running OS 10.7.5 on Macbook Pro with i7 CPU and 8GB of RAM. I'm connected to the Web at 3 Mbps. After the recent OS update, iChat has become unusable. Chat sessions are dropped more than once per minute! Video on both sides of the conversation either freezes or is badly pixilated, and the sound either stops for 10 seconds and then catches up at 4X the normal rate or it cuts out altogether. I'm tired of seeing the "Send to Apple" bug report window. How to fix this? I've tried adjusting bandwidth limits. No improvement. Doesn't Apple test thses things before releasing them?