Hello samdarabi - thanks for using the Slingbox Answers Forum!
Both the PRO-HD and the SOLO would use SlingPlayer and our SlingStream technology to watch your TV remotely. SlingStream optimizes video automatically as it is sent and received over the Internet.
You may want to check out this page which compares the features of both Slingboxes:
And this page explains more about how the Slingbox and SlingStream work:
If this doesn't help, please let us know. The more details and information you can provide, the better we (the forum community and Sling Media) can help.
The Slingbox Answers Forum Moderation Team