I'm sure everyone has heard of this issue over and over again. I myself have been attempting to fix it for well over a year. I've changed routers 2 times in that period (moved to a new place and swapped out routers to replace a crappy old WRT54G). The issue is simply that even on a 22mb down / 2mb upload any speed-test will net me around a 2mb down (upload lower), even if testing via the browser in the PlayStation 3. Interestingly enough, some user claim their older 40gb model is unaffected by this problem, whereas the newer 80gb and 120gb versions are those afflicted with the networking curse.
Here are the supposed fixes for this issue:
1.) Change your router to Wireless G only mode instead of mixed B/G. (Issue - People use Wireless N for the most part and this option isn't available. Also found it to not fix a damn thing.)
2.) Port forward the appropriate ports on your router or other networking devices, or alternatively set a DMZ for your PS3 and most likely set a static IP for it to to retain the DMZ. (This advice has proven to do Jack squat.)
3.) Plug your device in wired. (Not an option for everyone and very inconvenient.)
4.) Adjust the MTU to something below 1500. (This seems stupid at first glance, but may it be possible that the older Wireless NIC in the PS3 does not properly account for more modern wireless security standards that use a larger overhead in the packet size? I've seen some older NICs refuse to connect to routers with say WPA enabled or perform like crap on them.)
5.) Some users claimed to have alleviated the performance issue by simple leaving their WIFI wide open with no authentication. (Do I even need to mention how stupid it would be to consider this a fix? It does lend credence to the main issue being the wireless NICs authentication or handshake with certain security protocols).
I'm curious to see others findings on this issue and if anyone has found a reasonable "Fix". I'm almost surprised that Sony has not been sued in the form of a class action lawsuit over this very obvious networking defect. If nothing else they should want to make it right as its prevented me and I'm sure 100's of thousands of would be customers from purchasing movies and games off of their PlayStation Network. Especially with their new "Stream" function added to rentals, I've found that its literally luck of the draw on whether I can get past the "Your connection is too crappy to stream this". Obviously even that 2bmps is because finally when it allows it to, it will stream alright as long as we don't attempt to rewind or jump forward, which will cause it to crash and go back to the main PlayStation home screen.
I'm just so disappointed in Sony's lack of explanation or to even acknowledge an issue (as far as I know.)