Why is my wired Internet connection slow on my PS3?
Solution 1:
Here's the thing about data transfer and the device it's connected to. While I suggest you keep looking for a fix, the main thing about Bandwidth utilization is that even if a great quantity of data is being sent to your PS3 by your router, it's dedicated network processor can only process so much data, and Sony limits this to save on procedural resources to the highest necessary speed.
The PS3 uses a CELL processor setup with several modular CPUs, but just 256 MB of ram, so its ability to receive and process incoming data is quite limited.
I would still suggest you stick with the wired connection to limit latency.