SX adding pops, clicks, load noises to my samples.

[jiggity-j]

I'm kinda getting frustrated that my SP would add noises to my samples. This usually happens when I try to edit the loops points, but just now I was just playing some patterns and the SX hiccuped/paused for a second and then added a pop in a sample. Could it be the SX itself, or the sd card? I have 2 16gb class 6 cards, and one of them would always need to reformat. I bought the SX new just last Friday, but I've had an SX before(traded it away) and never experienced this. I will rock the OEM sd card for a bit to see if it happens to that. What I plan on doing is just make doubles of each sample. What cards are you guys using that works FLAWLESSLY?