The Slingbox (no matter which model you have) needs a connection speed above 600kbps (the higher the better) in order to work in a proper way. If you get only 187kbps, you will need to check and verify what external factor might be affecting your available bandwidth.
We recommend you to check with your ISP in order to know what is affecting your Internet service.
Note, I have this issue as well and when I search for support, Slingbox says they know about the problem but want the details so they can help fix, but then there is no place to submit especially if outside of 90 day support window.
I have slingbox pro hd streaming from US to switzerland since September 2010. It worked relatively smoothly for months with a normal speed of 2.5mbs. This works and is almost HD quality. However in December my slingbox slowed and I tried to get help but to no avail. My friend reset the slingbox and reset it then it worked fine again since first week in January when he reset. yesterday it slowed back down again to below 200kbs. I assume resetting will fix again for a while, but not sure why this is happening. it is not my service providers, happens on all computers, from everywhere and nothing but a full reset seems to help. Slinbox not offering customer support to fix a problem on their end and I believe this is happening to others as well.