Yosemite 10.10.3 GA-Z87N-WiFi + GTX 960 very unstable

Hi,

I've been working with my Hackintosh Mavericks for almost a year without any problem until my GTX 760 stopped working and my hardware store changed me without cost for a GTX 960 (GTX 760 seems hard to find now).

Then I realized that Mavericks doesn't have support for GTX 960 and I decided to install Yosemite 10.10.3 and here comes the nightmare. I needed like 4 clean installations until it worked (thanks to this awesome guide).

Now I can only boot ignoring caches, my audio didn't work (only the first time, after the first reboot I lost it), my chimera doesn't work and my Hackintosh seems very unstable freezing completely (sometimes I can't work with it 5 minutes).

This is my hardware list:

BitFenix Phenom Mini-ITX
Cooler Master E-600 600W
Cooler Master Hyper TX3 EVO CPU Cooler
Crucial MX100 256GB SSD SATA3
G.Skill Ripjaws X DDR3 1600 PC3-12800 8GB 2x4GB CL9
Gigabyte GA-Z87N-WIFI
Gigabyte GeForce GTX 960 OC 2GB GDDR5
Intel Core i5-4460 3.2Ghz Box

Any thoughts? Ideas? Clues?

I've noticed that using Magic Trackpad usually freezes my computer, anyone having similar issues?

Do you recommend me other bluetooth kexts to solve this issue?