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Q&A: MacFixIt Answers

This week readers e-mailed in questions about Target Display mode in iMac systems, RAM purchases for Macs, and more.

MacFixIt Answers is a feature in which I answer questions e-mailed in by our readers.

This week, readers wrote in with questions about the cabling requirements for using Target Display mode in new iMac systems, maintaining Snow Leopard after having upgraded to newer versions of OS X, RAM purchasing recommendations for Mac systems, and having a used Mac checked out by Apple or other technicians before purchasing. I welcome views from readers, so if you have any suggestions or alternative approaches to these problems, please post them in the comments!

Question: Using Target Display mode in new iMac systems
MacFixIt reader Steve asks:

I am trying to connect 2 iMacs so I can utilise one as an additional screen. The master has 2 Thunderbolt ports, so I run a Mini DisplayPort from that to the other iMac with a Mini DisplayPort (no Thunderbolts) then press F2 on the master hoping the older iMac will become a 'slave' screen. Unfortunately I get nothing at all, it doesn't say they are connected in the System Report under Thunderbolt or graphics/displays.

If you have a newer system then you might need to use Thunderbolt cables instead of Mini DisplayPort cables. See here for more information on this.

Question: Maintaining Snow Leopard after upgrading to Lion or Mountain Lion
MacFixIt reader Dan asks:

If I have already installed Mountain Lion will I be able to follow the instructions for keeping Snow Leopard when upgrading to Lion? I need to run a program that will not run on Mountain Lion.

If you have already upgraded then you will not have Snow Leopard installed anymore and therefore will not have a way to preserve it on a separate partition when upgrading; however, if you need Snow Leopard you can install a fresh copy of it to an external drive or to another partition on your internal drive, and then boot to it to run the program you need.

Question: RAM recommendations for Mac systems
MacFixIt reader Albert asks:

The last time I used Crucial RAM for my iMac it was a problem. I then purchased RAM from "MacDirectRam," a little more costly but it has worked for past 2 years without a problem. Presently a 32 GB set runs ~$269 plus tax. What are your thoughts? Is it worth it? OWC is about $195 for the same set so the prices are close.

My approach for RAM has been that if it works, then that's all that matters. Expensive RAM can go bad or be defective just like cheap RAM, but usually is tested more rigorously so the chances of this are less. However, spec for spec the RAM's performance will be quite comparable. As a result, if you buy cheaper stuff and thoroughly test it with Apple's hardware tests, then you should be good to go.

Question: Having a used Mac checked for errors by Apple Geniuses
MacFixIt reader Jonathan asks:

If I take a used Mac I just purchased to Apple's Genius Bar and they diagnosis it and it comes up 100% working and everything perfect then is there any possibility something could be broken or run into errors down the line, assuming I don't do anything to cause the breakage or error?

It depends on what the Genius folks do when diagnosing it (if they diagnose it). My guess is they would run Apple's hardware tests and check the hard drive for errors using Disk Utility, but without being certain of this (especially given that the Geniuses might use their own discretion as to what to do for testing) my recommendation would still be to perform your own checks to test the Mac's condition. There is always the chance of a hidden defect, but for the most part if the system passes these tests then it should be fine.

Questions? Comments? Have a fix? Post them below or e-mail us!
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