As many other MacPro users have discovered... it seems that the bluetooth reception range was less than a foot away from the computer... the mouse was skippy, and the keyboard would repeat characters often. It has recently been found that some of the Airport and Bluetooth antanae (and an unknown, unlabeled, unconnected wire) were mislabled (and in my case, only 1/2 were labeled) and thuse mis-attached after the bluetooth/airport option was added by Apple.
After much googling, I didn't find a decent tutorial or info on how to fix it, merely short posts on Apple's forums: "Swap 1 with 3 and yada yada. Your done." Also, to boot, only cable#3 and the BT cable were labeled (and possibly mislabled). So I figured it out after much research. I am also a visual learner and struggle with verbal or written instructions. I had to sketch it out. Here is the diagram I ended up making, and the steps needed to fix. If you own a MacPro and have horrible bluetooth reception, I suggest you look into this. Although look out, if something goes wrong, it may ruin your warranty.
I posted that a year ago... it seems that users are still getting this problem with new mac pros!
Here's the original Apple Support Discussion Thread: http://discussions.apple.com/thread.jspa?threadID=633522
Anyways, I made the original rough hand sketch diagram that seemed to help quite a few people on the Apple Forums, so since this issue is still pertinent I quickly made a .pdf intended to be printed out and followed during the fix. It has some diagrams made in illustrator, and labeled photos of my fixed Mac Pro. Let me know if there is anything I should change/modify. I hope this can continue to be of help to people. P.S. I am a design major and did this very quickly, please don't show my professors
http://www.thelocale.org/files/howtos/mac-pro-bluetooth-howto.pdf
mirror: http://web.mac.com/gcrowl/mac-pro-bluetooth-howto.pdf
So, in summary (if you are going to perform this, check out the pdf):
There are going to be four wires. For me, there were two unlabeled. One was short and disconnected (wouldn't reach the BT module), and the other was longer and attached to the upper airport port. Another was labeled 3 and attached to the lower airport port, and another was labeled (mislabeled) BT and attached to the BT module.
1. Detach upper airport wire (long, unlabeled)
2. Plug in previously detached short unlabeled wire into the upper airport port.
3. Unplug wire labeled BT from the bluetooth module. Put plastic shroud on it. This wire will be unused.
4. Take longer unlabeled wire that used to be plugged into upper airport plug, and plug it into the bluetooth module.
5. Enjoy.
My Airport reception ended up being much better, and my bluetooth reception is amazing. Before I could barely use my mouse and keyboard a foot away, now I can use it in another room in my apartment (as long as someone shouts to me what i am doing ). I have been running this modification for over a year now with no problems at all. Reception is still amazing on with Airport and Bluetooth. If you find that your bluetooth reception is completly unsuable, this might be a good place to start, it seems that as far as I can tell most that do have this issue are miswired in this way. Apparently apple still continues to deny this problem… Although hopefully we can help spread the word that this is indeed an issue, and this is a likely fix. I don't know how many are effected by this problem, but this fix has helped at least 20 people on the Apple Forum.
Digg This: http://digg.com/apple/Fix_Bluetooth_Reception_Problem_in_some_Mac_Pros