Help!! snapping crackle on playback with Cubase 8

Hi ive just purchased Cubase 8 PRO and having problems with playback on both old and new projects with a constant crackle noise!

i know that it has not being recorded as i’ve listened to most projects before on a previous version and theres no clipping on new recorded tracks. I was thinking its a buffer issue? when i increase the buffer on my MBOX2 the crackle becomes less BUT does not dissappear even when on its highest settings: 4096

Here is my Computer specs:
Processor: AMD A8-5500 APU with Radeon™ HD Graphics 3.20GHz
Installed Memory (Ram): 6.00GB (5.18 GB Usable)
System type: 64-bit Operating system, x64- based processor