I am constantly running out of hard drive space, so finally sprung for a new 4T WD Black internal drive.

I installed it into my 2010 MacPro tower in a standard hard drive slot and loaded several large projects onto it.

The playback of video is choppy - it'll play for a few seconds, then stop, then play really fast to catch up, then stop. Audio cuts in and out. I was able to painstakingly edit one project, and then it took three days to create a final exported file of it.

My first thought was that it was a 5400 rpm drive but that's not it, it's definitely 7200 rpm. It is a newer drive so I'm wondering if it's somehow not compatible with the MacPro?

I tried pulling the drive out and swapping it with a firewire enclosure that I have, and only 1.8 TB capacity appeared and it wanted to reformat the drive - didn't recognize it. The other drive (500GB) that I pulled from the enclosure works fine in the internal MacPro slot.

Anyone run into this before and have any ideas for me?

Editing on FCP7 but even playback of the raw files in VLC or Quicktime player does the same thing, and only on this drive.

1) Did you format the drive or used it as formatted by WD? Reformat the drive and see if that helps.
2) Run the AJA disk test program or the Blackmagic Designs disk test programs. They are free downloads.
3) The drive maybe defective. 4Tb is a lot to cram into one unit.

Likely the drive is formatted for Windows optimization. For MacOS use, use HFS+ or ExFAT (my preferred format these days)

The hardware or firmware in the external drive bay controller probably doesn't allow for 4TB formatting. Older chipset likely.

A single 7200 RPM drive will play back most compressed formats with decent performance. At the higher end, you may drop frames. A 5400 RMP drive will drop frames faster, even with compressed formats.

If you really want to make sure you don't drop frames, you'll need a RAID that has more bandwidth than whatever the fattest format you want to work with.

For the record, I'm working with LaCie external 3TB Quad Interface drives connected via Firewire800. Single drives in the enclosures, no RAID.

Pulling ProResHQ at 1080P with ZERO issues.

I'd bet the issue is the drive formatting. Or a faulty drive.

ADDENDUM: I've formatted all my externals for the last two years as ExFAT for convenience but ExFAT or HFS+ have never given me an issue.

Could there be a problem with firmware on the Mac not "recognizing" a 4TB drive?

In 2010 a single 4TB drive seemed a LONG way away...

Thanks guys. I did reformat the drive after installing, to the HFS+ Journaled. After a week I finally received a response from WD and it just says check it with Disk Utility, which I already did and no issues. I'll play with the speed test software and see what I learn. Maybe it's defective, although I didn't really want to believe that at the beginning. I did go ahead and order a new 4 GB g-tech external drive and that's been running like a champ, no issues.

There's clearly an issue somewhere. My best performing internal drive runs at 106.7 MB/s write, 105.8 read. This drive runs at 10.6 write, 9.7 read.

Once the needle jumped to 70 and then jumped right back down to around 10.

Must be defective I guess. Not sure what else to think? The tech guys at OWC said that the Mac should be able to handle it no problem. So weird.

Yup. Sounds pooched.