Maximum PC

Ok, I did a fair amount of searching here and on the web but can't seem to find a solution that works. I'm having an audio crackle/pop/latency issue. It's hard to describe, but at random points during playing audio I'll get a crackle or pop. It also sounds as if my music (being played through itunes and various other programs) is being slowed down ever so slightly at times. This is a recent issue Here are my specs (all drivers current):

Core i5-2500k (OC'd to 5.0 GHz, Stable, No Voltage Adjustment)
Asus P8Z68-V LX MoBo (latest BIOS [0703] installed)
Power Color Radeon 6850 (Catalyst 12.1 Installed)
Sound Blaster X-Fi Titanium Fatality PCI-E (Running Support Pack 2.5, Issue Present on Creative Drivers As Well)
12GB G.Skill Ripjaw DDR3 1333
500GB Seagate Main HDD
1TB Seagate Storage HDD
Windows 7 Home Premium SP1 (x64)

If other specs are needed please ask. The issue is present on my X-Fi card, as well as on the onboard realtek audio AND through the audio channel on my video card's HDMI port. Also, the issue didn't present until WEEKS after I OC'd my CPU, which runs under 50 C and stable with the Zalman cooler I have installed. I did back it off to check, with no luck. By default, I keep the Realtek disabled through the BIOS as it's never used. The onboard audio on my Radeon card is occasionally used to play video/audio through my living room HDTV.

I'm really at a loss and I can imagine I'm the only person with this issue... Any help would be GREATLY appreciated. I'm a DJ and run a weekly podcast and that crackling is driving me up the WALL.

Check in the bios for the three voltages your psu outputs...3 volts, 5 volts and 12 volts. They should all be within 5% of the three figures I gave you. If not, switch out the psu and see if the crackling issue goes away. Beg, or borrow one. I hate to have you buy a new one and it not be the issue.

Nasty

Voltages are within 1%. Thank you so much though, I hadn't thought to check that. Also, as of today I have now Reformatted, removed the X-Fi card, checked all cables, backed off my overclock and pulled the mismatched 4GB DDR3 kit out of my system leaving an 8GB DDR3 kit. It's such a subtle thing occuring at intense points of audio during music and games. I've tried switching between all of the different bitrates and frequencies, makes no difference. I'm really at a loss here and I hope I don;t have to RMA this motherboard, it's less than a month old! I've adjusted every BIOS setting I can think of... Nothing works, just get this same crackle regardless of whether I use speakers, headphones or my Hi-Fi system routed through my DJ mixer... So frustrating. Thanks to everyone who's peeked at this so far though.

Edit: The onboard audio on this mobo is the Realtek ALC887 HD chip

Are you sure it isn't the speakers themselves that are causing the crackling? Try a friends speakers to check this out.

Nasty

What make model and wattage PSU are you using? What happens when you drop the overclock to stock? What is the temp of the Z68 chipset?

Yea I've tried multiple sets of speakers, and my headphones. No avail.

My PSU is a Thermaltake Toughpower 700w, it's been rock solid for the 3 years I've had it, voltages look fine. Chipset temp is good, sitting at about 30 C. Thanks again!

Is the music that is slowing down, stored on a internal or external disk? Is it on the same drive as itunes or seperate? The crackle and pop are electrical interference, the slow down is definitely an oddity. How old is the drive, have you tried a different cable for the drive?

Problem solved!

Basically, my Wi-Fi adapter was creating latency in the system, even with the onboard LAN disabled. I can only speculate, but it may have something to do with the Z68 chipset not directly supporting the PCI bus anymore (I believe? kind of been giving myself a crash course on the subtle changes in the newer Intel chipsets). I found a thread on another forum that had no less than 60 pages of replies. Skipping to the end, I found that people were having success using a DPC latency checking tool, and disabling devices in device manager one by one until the latency droped below acceptable levels. I'll post it below for anyone who has this problem in the future. We're back up and running! Never would've guessed my 6 year old Draft-N adapter would be causing sooo many problems!

Thanks for the help all!

DPC Latency Checker Here!