Adding a 4th Hard Drive

The answer is basically no.

When you have a bunch of hard drives, sometimes you have a little latency while it wakes up the sleeping drive. This is less with solid state drives.

Basically because you have more drives it is more likely that the one with the stuff you need is sleeping. Spin up time is usually a second our two.

Only thing to make sure of is that you have enough power capacity in the power supply (which you likely do.)

I just added another SSD for samples as well, now using 7 internals w/o any issues. ( on my Platinum Studio built by Jim)

+1 to the above, the only thing to check with your MB is what happens if you go to x4 mode on an NVMe M.2 drive. On mine, that takes up (and takes out) the SATA 5/6 connections, but that NVMe makes one rather nice sample drive.
 
Oh, the other one that was sort of funny when I did this... BIOS and Windows both recognize the drive, but Windows Explorer did not... had to go into Disk Management to bring it online after installation.

BobF
Your specs show you already have five 
 

I have more than that if I count all of my outboard drives. I have three internals . I never liked outboard drives very much. Easy to install yes. They use up valuable usb ports though. My MOBO only has one usb 3 port. The rest are 2.0. They decided to put those all on the back except for one. I would almost rather eat tarantulas than attempt to crawl to the back of my studio desk. I could get lost back there for months. I have a port hub but you probably know how they can muck things up occasionally. The ports are becoming more and more valuable. Waves licenses, my mouse transmitter,etc. I might be getting a dongle. Growing tired of cloud authorization with my McDSP plugins.
The cords they give you with outboard drives are like 4" long. Can't go very far with that length.
 
Thanks to Jim and others for your helpful comments. I noticed one of my drives is giving me a red volume indicator. I believe I have maybe 38gigs left on it. With platter drives it was never a good idea to go within a mb of filling the drive up, or so I have been told. Not sure about SSD. Do SSD's begin to loose capability when filled to almost full? If not is the red indicator intended for HDD's?

slartabartfast
...I assume everyone has their DAW power settings that way, and no one is using a "green drive" that does power/speed down throttling automatically.

 
I have 7 drives in total and 2 of them are "green". The green drives are only used for storing things that don't affect the audio engine, i.e. archives, backups, manuals and other reference materials.

slartabartfast
I assume everyone has their DAW power settings that way, and no one is using a "green drive" that does power/speed down throttling automatically.

Not me. I really never have a problem with my drives. I do let them turn off to save power. I suppose this could be a mistake.

When I'm recording a band and get bored i might wake up a sleeping drive to do some house keeping. I suppose there could be a buffer risk there. I record with digicheck. When there is a problem, I usually lose one even buffer across all tracks. I keep the buffer maxed to reduce risk when no one is listening to the recording. This loss of a buffer has usually happened when i mess with cakewalk while recording with digicheck. Cakewalk will pop that buffer. Hitting record enable on tracks pops the buffer for example. This happened once while showing-off cakewalk to a pretty person concurrent to recording a band.

I only know of one time when I lost a buffer due to hd activity. Here's what happened. During a long 16 track recording, at intervals, I save the current recording and start a new one. When the intervals are fairly short the files aren't too big.

When done correctly, it is as fast as renaming the file I'm saving. Fast in other words.

But if I've already renamed it and save it again, it makes a copy. I did this once, afraid i had forgotten to save it and terrified to lose it. So, at @1 gig per hour of music at 88.2 the file I saved was probably close to 30 gigs. Took a minute on an old laptop 7200 drive. I made the band wait for it. I got a few rolled-eyes but they like me and waited. Once done, I immediately started recording and the band kicked right in. They were tired and finishing up to go home. In a repetitive section at the front of the song, I lost a buffer. Idk why but something to do with that large copy I'm sure. I was able to copy one of the repeated beats over the lost buffer and the band never knew (unless they read this).

Can you tell which beat?
http://gswitz.blob.core.w...R_20_TakingOnWater.mp3

The nice thing about losing exactly a buffer is you can know precisely how much time too slip back in. Copy paste, cross-fade, who says I lost a buffer?

...

When using cakewalk and tracking or performing on the recording, the drive being recorded to is obviously not asleep. No one will wake a sleeping drive. No risk.

Jim Roseberry
I've got 10 internal drives in my main studio DAW.
You'll be just fine...  

 
Yup - I have 2 M.2 NVME 2TB drives (boot and most used sample libs), and 2 TB SSD's and a couple of 4 TB SSD's cranking away - no issues, as long as you have decent cooling and a healthy enough power supply.
 
Bob Bone