Blog Archives
#MacOsX : Reset NVRAM, PRAM and SMC
Sometimes after a software (system) or hardware upgrade even Macs can have some problems; if you have tried every solution without success you could try this.
Every Mac stores certain settings in a special memory area even if it is turned off. On Intel-based Macs, this is stored in memory known as NVRAM; on PowerPC-based Macs, this is stored in memory known as PRAM.
Resetting NVRAM and PRAM may solve lot of problems and could be required if you upgrade SSD or Mac firmware (more tips on SSDs here).
Another step to try is Resetting the System Management Controller (SMC). An SMC reset should only be attempted after all other standard troubleshooting has been performed.
#MacOSX : Disable Hibernation & SSD Tweaks
SSD are based on NAND Flash which have limited writes life. Currently 25nm chips support 3000-5000 cycles then they become read only.
This limitation makes very important avoid unneeded writes on the disk.
Moreover power save technologies can give some trouble (of course on SandForce controllers).
So this are some steps to Tweak your host system to give you the best experience:
- Turn off hibernation. To do this, open terminal app and type:
sudo pmset -a hibernatemode 0Enter admin password and let’s do it the magic.
This will prevent GB of writes every time you close the lid of your notebook. - Remove unused hibernation file to free up as much space as your RAM:
sudo rm /var/vm/sleepimage - Open System Preferences and go to Energy Saver, than uncheck
Put the hard disk(s) to sleep when possible
both on Battery and Power Adapter tabs.
This will prevent disk freezes and beachballs. - If you have a SATA 2 interface and a Nvidia chipset on your Mac, check to have 3 Gbps Negotiated Link Speed.
Go to Serial-ATA section in System Information app to take a look of your disk(s).
This will ensure optimal performance of SSD.
NOTE: there are more Hacks, like enabling TRIM for non Apple supported SSDs but they give more troubles that other therefore I advice against to engage in similar enterprises.
NOTE 2: WARNING!!! Apple MacBook Air and MacBook Pro Update 2.0 seems to change the way “safesleep” is handled. If you currently have safesleep disabled in order to free up the drive space required by the sleep image, this will cause it to come back and even setting hibernatemode = 0 won’t change it. Quick untested FIX:
cd /var/vm
sudo rm sleepimage
sudo ln -s /dev/null sleepimage
whitehatty 