Without reading this topic, I have one contribution.

user Satoshi posted shortly before vanishing in 2010:

"I tested it on a slow 7 year old drive, where bandwidth and CPU were clearly not the bottleneck.  Initial download took 1 hour 20 minutes.

If it's taking a lot longer than that, certainly 24 hours, then it must be downloading from a very slow node, or your connection is much slower than around 15KB per sec (120kbps), or something else is wrong.  It would be nice to know what appears to be the bottleneck when that happens."


Given that every time I start bitcoin-qt and the connections indicator goes to healthy green, but the initial download takes more than 24 hours, I would say his original vision for how fast the download for new users should be, is not panning out, and we're not even at 1% of the paypal transaction volume yet.

So what exactly is the problem? that the block chain is growing faster than the average users broadband connection speed, or the network and software design is currently not able to deliver the data as fast as it should -- even after you poke holes in your firewall?