WD My Passport 4TB - Low write speeds

I bought 3 motnhs ago a WD My Passport 4TB. Got it all filled with media content. I arrived to realise these days that the speeds on it are very slow.

I remember I ran a black magic test at the begininf and it was showing roughly 80MB/s write speeds. Now it won’t go over 35’ish MB/s max write speed. More than this I noticed that on a sustained load (like download a big file) it keep around max speed and than it just drops to less than 1MB/s (and it’s not the internet connection). I replicated the same with black magic leaving it running and getting in the end the low speeds.

hdd is formatted macos ext guid. I use it on a macbook pro 2017 so really hardware support should not be an issue. os is mojave 10.14.4 (maybe is something related to beta? but i wouldn’t think so because i tested another older drive and it performed better than this one). checked it with mac os first aid and all looks fine. checked it with wd utility (roughly 12 hours) and all looks fine.

any suggestions? is that a reason to consider warranty already?

any feedback would be appreciated.

P.S. past days i did a lot of internet searches about this and I came up with nothing except that 35MB/s is slow for this drive.

LE: last resort would be to completely erase it and test again - but the problem is i have no space to dump almost 4TB of data.

Hello cezar.cretzu,

There could be multiple reasons due to which you are experiencing this issue. Maybe the folder that you are transferring to the hard drive contains several data on it in a form of clusters which kills the data transfer rate. Try to transfer a single archive large file on the drive and check if it makes any change.

The drive is healthy or fine as you have checked using WD Utility and Mac First Aid. However, if the issue still persists while the drive is behaving fine or healthy, it would be best to contact WD’s Support for more details about this.

did everything. health check. clean os install. clean hdd. apfs. macOS extended. fat. black magic. file transfer. big one to be sure. always my transfer rate was half the one advertised. returned it already. working with the cloud now and planning to get a 2TB T5 from Samsung.