Indeed generally it wouldnt, but it is however a direct indicator of maximum bandwidth.

In short, it means PSN can bog down significantly faster than XBL.

*Sigh*

When talking about Internet speed, it's Mb or "Megabits".
MB is "Megabytes".

Mbps is Megabits per second.
There are 8 bits in a byte, hence 8Mbps would be equivalent to 1 Megabyte per second.

As for this "speed test" it will vary by region, due to various factors.
Generally though, Microsoft has more servers and buys more capacity over Akami and Peers with more providers than Sony, so they usually always have the edge.

the screenshots make that kinda obvious.

was proud of my 100mbps down and 5mpbs up but now I hate it.

So from looking at this thread, it's not about comparision, it's about boasting about your internet connection? :P

I'll stick with my 50mb, thanks. My ping is usually only about 30-50.

purely about network maximums, i simply answered questions regarding the net.

Ping is 3-9ms when actually playing games.

There is of course a huge caveat to your results.

1. The download speeds for PSN are far far beyond the average household connection (which is to say nothing about how Over Powered your connection is)

2. Connection speeds are limited by region.

No it doesn't mean any of those things, certainly not the latter.

1) You are reading a number reported by Sony's own client running an artificial measurement.  Unless you can tell us how it's programmed and if it's measuring the same way in terms of packet size, count, and service type that Microsoft's is, then you can't meaningfully compare it to Microsoft's number.  There is no particular reason for Sony to optimize either their server or their client to do 600mbps on one line for this kind of bandwidth test.

2) Your single line speed can't be used to infer how fast PSN can bog down.  That would depend on the number of servers, and total bandwidth that you can not infer from a single line.

Anyhow, I would not be surprised that Microsoft has plenty of bandwidth on it's Japan servers because there's almost nobody online. ;-D

1) both systems use randomly generated data pulled from the associated server and track the speed at which said file is downloaded, then the downloaded file is uploaded back to the same server. The test is identical for both except that the XBO test runs a latency test immediately following the receipt of the uploaded file.

2) the used connection having a maximum throughput higher than the services itself is the closest you can get to measuring the maximum, and this is the closest most people can get to seeing he differences in high bandwidth environments, the results are clear for anyone not tainted by bias, Microsoft servers have a signfificantly higher bandwidth peak.

If someone on google fibre in the states with both systems feels like chiming in with their own test results then by all means do, or if anyone in the EU has a 700mbit+ connection, then the same.

1) How do you know that they are the same?

2) This is not bias.  I'm not telling you X > Y or X < Y.  I'm calling you out for drawing conclusions on face numbers, while ignoring any number of things that could limit the numbers you see, as well as their relevance.

Do you know Microsoft's requirements?

Recommended Minimum Requirements

Microsoft recommends a minimum download speed of 3 megabits per second for online gaming, 1 megabit per second for SD video streaming, and 3.5 megabits per second for HD video streaming. Minimum upload speed for online gaming should be faster than 0.5 megabits per second. 

My conclusion:

a) both services seem overprovisioned at the time you measured.

b) there was no real world measurement that you were able to make which showed the difference.