Q: So sick of Magic Mouse problems...

It might not be the mouse that's the issue. Test your mouse with another computer.

I would it is likely due to interference from the USB 3 card you have installed:

http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb3-frequency-in terference-paper.html

http://www.macobserver.com/tmo/article/usb-3.0-hard-drives-can-cause-wi-fi-inter ference

/When was the last clean install?

I had a USB extension that 'messed up' and interfered - I don't use BT and for kb.mouse they are fine inexpensive 3rd party devices mostly though I do use my Apple Pro keyboard(s) (PC and Mac Pro)

There have been people today asking about the best or what USB3 cards work and are supported (and they change over time, new chipset, new added support or lack thereof)

ATI Radeon 4870, SeriTek eSATA PCIe card, Inateck USB 3.0

I was a big supported of SeriTek going back to early SATA days in 2003 but have not used any in nearly 6-8 years.

There is no reason to use something you don't like, you have lots of choice and options. BT battery and the aluminum shielding as well as potential interference in the local environment.

One of the better and oldest repository of user reports - and should be one primary stops before buying or choosing, as well as for trouble-shooting

http://www.xlr8yourmac.com

I would add MacIntouch but their "reports" are impossible to wade and find the quote in long reader 'discussions.' while MacRumors forum is easy to search - and keeps topics to as few threads as possible. And there are others.

But #1 to troubleshoot any soft/hardware would be a clean OS install, and remove any and all 3rd party changes to hardware. Then introduce one thing only at a time - and watch behavior.

I would keep 10.8.5 on one drive (partition if you must), same for Mountain Lion and Yosemite. (Upgrade to PCIe- SSD at this point too)

I would try to upgrade the 4870 to a more modern card with current OpenCL 4,x and more VRAM to handle and support 10.10

Try to eliminate wifi or bluetooth interference - move any other devices away from your desk, especially phones with many transmitters. I find an iPhone will interfere with wireless mice if iTunes wifi syncing is on.

Consider moving the Mac Pro into line of site if it is away from your mouse. Bluetooth can have issues with objects between you & the receiver. If you are working on a metal desk move away from it to see if it receives any better. Also try using a wired keyboard for a while if you have a Bluetooth one at the moment.

What batteries are you using? Have you tried standard alkaline AA batteries? Rechargeable batteries are a slightly lower voltage than disposable AA's, it can cause a difference with some devices. I believe Apple shipped NiMH rechargeable batteries for these mice at one point with a charger so they should work OK, but it is a simple thing to change & test.

Mice can also behave erratically if there is hair or fluff in or near the detector. Ensure that is clean. Also try another mouse mat, some surfaces make Apple mice ping around the screen like crazy.

Personally I prefer other mice like ones from Logitech or even Microsoft, but finding one with the touch based scrolling may be tough.

I understand that the other device works, Apple use different hardware & antennas to HP hence the need to see if it works better when you are closer to the Mac & it is important to remove other potential sources of interference - it is possible for RFI to effect the mouse itself not just the radio waves in the air.

Another option is to try a safe boot it may indicate that third party software is at fault, just bear in mind that graphics support will be poor so some mouse lag may simply be how the graphics operates in safe mode.

Try safe mode if your Mac doesn't finish starting up - Apple Support

Limited graphics performance in OS X recovery or safe mode - Apple Support

Safe mode is similar to running from a clean install but you could also boot from another install to be 100% sure the OS & installed apps are not at fault (as The hatter eluded). A USB external 16GB or more is suffice or use a partition on an internal.

I don't have the magic bullet answer you seem to want but you have to be willing to accept some advice & try things if you want to resolve it yourself (otherwise take it to an Apple store & ask them to resolve or replace the mice).

I heard some people sorta resolved it by leaving one of the covers open on the mouse.  Yeah,  it doesn't work...that's just dumb. bluetooth can be fussy on the Mac pro.  I used to have a magic mouse with the fussy bluetooth. I solved it by buying an iogear BT USB adapter that plugged into the front of my mac Pro...I think it  was around $20. Eventually after it died, bought a Microsoft mouse with a little usb reciever.  It's been pretty reliable but it's not bluetooth.

about the only way I could think to fix this would be to apply the famous "bluetooth fix" to the bluetooth card inside your Mac pro. Some bluetooth wires might have been mislabelled, and switching the bluetooth wire to #1 and disconnecting and covering the original may improve your bluetooth performance

but.... those antenna connectors are awfully tiny and you need a steady hand and lots of patience.....

good luck to you

JB

well you may be right about that., Wakko. I wouldn't say "no way"- maybe not that often or a slim chance that...

This is all I have to go on for this-some people have said that their bluetooth performance in the 2008 mac Pro's maybe the 2009 ones  was kinda lousy

and they got better bluetooth performace by switching wires. This may or may not work for you. I recently installed a bluetooth and an airport card in a 2008 mac pro with the help of another gentleman, lots of patience,  effort and a magnetic screwdriver, *  and in that, the bluetooth card was right next to/on top of the airport card, so your mileage may vary.  I'm looking at a combo card myself as I have the original 802.11 card in here, plus the original bluetooth card as well. I think that one is powered by some kind of usb kludge, so you have to plug it into a usb socket somewhere along the line. Still, if it works better than what you have now and it isn't super hard to install, maybe spend the $90 and go for it...I might be wrong though

Helloooooooo, Nurse

JB

*finding those little wires was great fun, too. they were well, well tucked under the logic board, but eventually I got 'em out  and connected.  Didn't swear once while I was doing it... Gee,you'd almost think that Apple Didn't want us to install it, with all the trouble they went to.....