I have a good connection. You can test your download speed on your PS3 in the connectino status or going to the web browser ad running a speed test. An easy website to run a speed test at (without a bunch of crap in the site) is:
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I have comcast cable internet. d/l speed about 20 MPS and u/l 2.5 MPS. I have my PS3 hardwired to the router. I have my PS3 setup on a static IP address that I assigned so it doesn't conflict with any other device in the house. I also have the PS3's IP address set in the DMZ and have all the ports forwarded. Lastly I did not enable uPNP on the PS3 and the router. this seems to work best with my connection. Others have uPNP enabled so play around with that.
If you need help with configuring your router... check out portforward's website:
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Hopefully this helps. Let me know if you have questions and I'll be happy to help.