Ask TUAW: iMac processor upgrade, 27" iMac as display, wireless input devices, and more

Happy holiday, and welcome back to Ask TUAW, our weekly troubleshooting Q&A column. This week we've got questions about upgrading an iMac processor, using the 27" iMac as a display, sharing a Magic Mouse and Bluetooth keyboard with a Linux machine, and more.

As always, your suggestions and questions are welcome. Leave your questions for next week in the comments section at the end of this post. When asking a question, please include which machine you're using and what version of Mac OS X is installed on it (we'll assume you're running Snow Leopard on an Intel Mac if you don't specify). And now, on to the questions.

sena720 asks

I'm thinking about buying a new 21.5" iMac but I'm really thirsting for a Core i5 (or i7) CPU. Is there any way Apple would put one of those processors in my iMac? Or is there a way someone handy with computers could switch in the CPU? I used to build computers when I was a teenager but I haven't done that in a long time now, although I figure if it meant having a Core i7 I could manage it.

Unfortunately, I do not think it would be feasible to do this. While it does seem that the iMac CPU is socketed, the i5 and i7 not only use a different socket, they also use a different chipset than the Core 2 Duo. So even if you managed to disassemble the 21.5" iMac, you wouldn't just be able to drop in an i5 or i7. Check out the iFixit teardown of the 27" iMac to get an idea of what is involved in taking one of these apart.

George asks

With the new 27-inch iMac, I understand that if you buy two you can hook them up so that the second iMacs screen becomes an extension of the first screen. So you would be using the second iMac as an additional monitor. However, my question is, is it possible to put mac os x server on the second iMac and have that running as a machine on one's network, at the same time as it's screen being used as an extension to the first iMac?

I've actually been wondering about this myself, and as Steve noted earlier today Apple has given you the scoop on how TDM works on the 27" iMac. Check out this Apple Support note; as you can see, the "monitor" iMac actually has to be running and placed into "Target Display mode" and accordingly "applications running on the 27-inch iMac computer remain open and running while it is in Target Display mode." So presumably that would mean that you could have the "monitor" iMac running on the network. Now whether this would work on OS X Server I can't say for sure, but I don't really see why it would not (I guess the question is whether it has the Target Display mode support baked in).

NT asks

I have an Intel Macbook running 10.5 that is connected in my home network to a Intel Mac Mini, also running 10.5. I want to be able to run backups of my Macbook to an external hard drive connected to the Mac Mini over the network using SuperDuper. I tried this, following the SuperDuper help files, but it was so slow that I gave up after 30 hours (only did half of the 160 gig drive in this time). I realize copying files over the home network is sometimes a bit slow, but not that slow. Am I doing something wrong? Where is the bottleneck- the router, configuration, or SuperDuper?

Here's my suggestion: connect the external hard drive directly to the MacBook and run SuperDuper! to clone the drive. After that is done, unplug it from the MacBook and connect to the Mac mini. Now when you do future backups just use the Smart Update feature of SuperDuper! and you won't be copying nearly as much across the network. Hopefully that will resolve your problems.

Patrick asks

I have an early 2009 MacBook. I have been thinking about getting a wireless keyboard and and magic mouse for it. If I were to do so, what are the chances I could share these (on an occasional basis) with a Linux based PC? Alternatively, if I were to buy a wireless keyboard and mouse for the Linux box, could I use them with my MacBook?

Almost certainly the easiest thing to do would be to get a wireless keyboard and mouse combination that appears to the computer (Mac or Linux) as regular USB input devices via a little USB dongle. That way you could simply move the dongle from one computer to the other when you wanted to change over. Most of these non-Bluetooth sets from Logitech should work fine. I would not really recommend getting a Magic Mouse or Apple keyboard for Linux, since the driver situation is so unclear. I did find some instructions for using the keyboard with Ubuntu, but I personally don't think it would be worth the hassle.

Richard asks

I'm looking at buying a new Quad Core iMac but I'm disappointed at the limited hard drive options available from Apple. Is there any performance to be gained by using a fast Firewire 800 Drive to boot from and then using the internal drive as backup? I was thinking about a GRaid drive from G-Technology. I'm mainly using my Mac for Modo, Photoshop and Final Cut so I can definitely take advantage of extra speed but can't really justify a Mac Pro for my home computer.

Check out this exhaustive discussion from the Macintosh Performance Guide. While this guide is focused on the Mac Pro, he does offer some thoughts on the single drive Macs like the iMac. His conclusion towards the bottom is this: "Even though a 7200rpm internal SATA drive in a MacBook Pro, iMac, etc is fast when empty, filling it up as little as 20% will show significant degradation in performance in the remaining free space. Quite probably, an external Firewire 800 (or eSATA) drive will outperform it, especially with a 3.5" 1TB drive."