Just installed TeamViewer on my three PCs. I have my main PC, one for recording TV and the other for general testing of programs or Operating Systems like Ubuntu. I have found that my main PC has dropped it's download speed so much that it is only OK now for emails. It should be 60MBs (that's what I get normally with Virgin), but sometimes it's as slow as about 6MBs.
My TV PC downloads at 60MBs but my testing PC is down to around 8MBs if I'm lucky. I thought I had a problem with my modem/router so I swapped the Ethernet leads around and put a new one on my main PC. It made no difference.
My wife's laptop is on Wi-Fi (no TeamViewer installed) and works at about 27MBs at the other end of our flat so now I think it must be TeamViewer. As I can still download OK on one PC, I will leave it for a while as I need to work on a friend's PC regularly to service it for her. It's a bit of a pain overall. Any good solutions or tips would be much appreciated as long as they're not too complicated :-) All PCs run Windows 7, have two or three core processors and adequate Memory.