Q&A: MacFixIt Answers

Readers ask about the power usage of memory upgrades, and more.

Topher Kessler MacFixIt Editor
Topher, an avid Mac user for the past 15 years, has been a contributing author to MacFixIt since the spring of 2008. One of his passions is troubleshooting Mac problems and making the best use of Macs and Apple hardware at home and in the workplace.
Topher Kessler
4 min read

MacFixIt Answers is a feature in which I answer Mac-related questions sent in by our readers.

This week, readers asked questions about whether or not a memory upgrade will result in more power draw and affect battery life, managing a nonfunctional SD card after a crash, how to dismiss update notifications for one application vs. another in the Mac App Store, and how to undo a command that forces the system to boot to Safe Mode at each start-up.

I welcome contributions from readers, so if you have any suggestions or alternative approaches to these problems, please post them in the comments!

Question: Memory upgrade power draw
MacFixIt reader Larry asks:

I tested out the new 4GB Mac Air and -- as expected -- got terrific battery life. I bought an 8GB model and it's too early to tell how good the battery life is. Do you know if adding 4GB of memory will affect battery life? Some say that it requires more power for the extra memory. If it had a hard drive you could argue that it would reduce power consumption by reducing caching but the Air - as you know -- has fast flash storage so I'm guessing that's a wash. Any thoughts?

Some RAM modules may draw a touch more power than others, so you may see a small impact on battery life, but for the most part this should be negligible. This is especially true if you are replacing current memory modules with ones that are just higher capacity. For a system that you are adding more modules to (such as a Mac Pro, where you might be keeping the old modules installed), then you will see a greater amount of power draw, but for the laptops you are usually swapping out the current memory with larger capacity modules, so the difference in power draw should be minimal, especially for systems with built-in memory like the MacBook Air.

You are correct that if the system used a hard drive, then at least for large tasks the extra RAM would help prevent the system resorting to the hard drive, and thereby help prevent unnecessary power usage, but for an SSD this impact will again be minimized. SSDs do have sleep and low-power modes, but the difference in power draw between these and full use is far less than that for conventional hard drives.

Question: Nonfunctional SD card after crashing
MacFixIt reader Hanousek asks:

My Mac stopped reading my SD card after a crash. Is there anything I can do?

The crash may have corrupted the card. You can try reading the card in another system, or in a device like a camera, and see if that will result in it being readable, and then format it to see if that can reset it to a usable state for your Mac.

Question: Dismissing update notifications for one app versus others
MacFixIt reader Rob asks:

Regarding updates in App Store, and the Notification Center alerts for newer versions:

This is a nice feature that I like to leave turned on. But is there a way to turn off the update notification for a single app that I have chosen not to update?

Specifically, I use Version 1 of Skitch. I despise later versions and do not want to update. However, Notification Center and the App Store continually remind me to update this software.

You can hide an update by going to the updates section of the App Store, and then right-clicking it and choosing "Hide Update." You may need to expand the update section to access individual updates underneath it, and hide them. Unfortunately this is the limit of what can be done for customizing updates, as the notifications are for the App Store program itself, so they cannot be set to only go off for certain updates.

Question: How to undo forcing the system into Safe Mode at each start-up
MacFixIt reader Dean asks:

I was having a problem booting into Safe Mode, so I typed the sudo nvram boot-args="-x" into Terminal, but now the system gets about 25 percent, then reboots. It's doing this over and over and over again. What do I do to reverse the sudo command, if I can't get the system to boot up?

The "nvram" command sets variables in the system's PRAM, so reset the system's PRAM by holding down the Option-Command-P-R keys immediately after you hear the boot chimes at start-up, and hold them until the system resets again. This should clear the setting and have the system reboot without the command to boot to safe mode.

Questions? Comments? Have a fix? Post them below or e-mail us!
Be sure to check us out on Twitter and the CNET Mac forums.