iMac Fusion Logic Pro X Issue: Crackling and Delay [SOLVED]

Hello. New guy here and this is my first post.

I'm guessing this is a simple fix but I've searched and tried my best to figure it out before posting so I'll get to the issue. I just got my new iMac yesterday and when I try to play my guitar through Logic Pro X, I'm getting a crackling and delay on the track. It's weird.

If I change the I/O buffer size and click "apply changes", everything sounds great... for a few minutes and then the sound degrades and delays. Change the I/O buffer size to anything else and it sounds great again... wash, rinse and repeat. Same problem.

My Mac is a 21 inch and it's brand new. Maverick, 16GB Ram, 1TB Fusion hard drive, Reason Balance AI. Guitar, tube preamp, Reason Balance, iMac. It should be simple. I was running Logic Express on my 2007 iMac and using the same setup with no problems.

What am I doing wrong? I'll keep reading and looking for the answer. Thanks in advance!

I believe you have been bitten by the notorious Fusion Drive bug.

https://discussions.apple.com/thread/5428602?start=0&tstart=0

The consensus is that the Fusion Drive sucks for Logic because it's constantly moving files.

Not really.

The problem is the latest iMacs with the Haswell CPUs and the fusion drive.

Info on issues regarding 2013 iMacs with Fusion Drive, USB2/3 and Driver incompatibility with 10.9: Apple Support Communities

Seems that Mavericks 10.9.2 is the fix but I'm not Mac literate enough to figure out how to get my hands on the beta.

IF they fix it. So far in the developer builds, no talk of audio issues. Just Mail, graphics and networking.

Update:

I contacted Apple support. They were not much help but they were going to get someone with Logic Pro X experience to get back to me. That didn't happen.

I took my iMac to the Apple store near me. I figured I would just exchange my iMac for one with a standard hard drive instead of the Fusion drive and they could yank the 16GB RAM from mine and put it into the new iMac and I'd kick in another $100 ($200 difference from a Fusion hard drive and a standard 1TB SSD drive) and buy a wireless external hard drive for backing up both our computers. Bob's my uncle. BUT... they can't do that because the RAM is soldered to the circuit board and doesn't come out like it did on my old iMac. So I took home my iMac and decided to think about it a bit longer.

THEN I got an email from Apple.

"You have been selected to join our AppleSeed Program. If you accept, we will provide you with pre-release versions of OS X Mavericks updates to install and use. While trying out this software we ask that you provide us with your feedback. Our program includes a bug reporting system and an exclusive online discussion board community for our participants. Become a valuable part of the software development process, and help us make this software update its very best! If you would like to be a seed volunteer and help Apple release high-quality software, follow the instructions below."

BUT 10.9.2 wasn't yet ready for seeding. So I waited a couple more days and decided to return my iMac. How do I know when 10.9.2 is going to come out? So I took my iMac to the Apple store once again. On the way there, I get another email from Apple. 10.9.2 is ready for me to download so I downloaded it right there in the store onto my iMac.

I brought home my iMac and set it up and wired in my audio interface. My rig at the moment is guitar into Mesa Boogie Preamp Rectifier Recording rack unit. I got everything hooked up... and it works perfectly!

No crackling. No latency delays. No drop outs.

I/O Buffer is set at 32. Latency is 5.8 ms Roundtrip. No problems. Sounds good.

SO. If you have a new iMac with the Fusion hard drive and OSX Mavericks 10.9.1. Relax. 10.9.2 will be available very soon and your problem is fixed after you download it.

Thanks for the report Torren61.

Very valuable information.

Thanks for the report Torren61.

Very valuable information.

You're welcome! I was so close to shipping this Mac... back. I have had excellent customer service from the Apple store personnel. I'm a bit disappointed with the lack of further communication from Apple's customer service. I feel like they should have emailed me or called me and let me know what the plan was. However, as long as the problem is solved, I'm a more happy camper.

Is everything ok with Imac fusion drive and logic x!?

I want ot upgrade my mac book pro to an imac but still not sure about the fusion drive!?