Hard Drive Unusable When Extracting

[PiERiT]

When larger downloads are extracting, the hard drive being used can't effectively be used for anything else. For example, if I try and download something else, it gets massively throttled (300Mb service barely nets half of that during this time), or if I'm streaming something over LAN from that hard drive, the streaming freezes or gets really choppy. All of this clears up as soon as the extracting finishes.

I've looked at resource monitor when this happens and SAB is often writing to the drive at 70-80MB/s, which doesn't leave much for anything else to happen when hard drives typically only do around 100 if I'm not mistaken?

Short of using SSDs for storage, is there anything I can do within SAB to fix this? Can I tell it not to exceed 50MB/s when extracting to leave some resources for other tasks?

Edit: I should note that I use Windows and have the -t0 par2 parameter, but I don't think it applies to extracting, only repairing.

Edit2: I ended up grabbing a small spare SSD, throwing it in a USB3 enclosure, and using that as my incomplete folder. Working pretty well so far.

[sander]

What kind of hardware is SAB running on?
Is the hard drive inside your Windows computer, or USB, or a NAS-drive?

[PiERiT]

SAB itself is running on Windows, i5-6600k w/ 16GB DDR4 RAM. The drive that was initially being written to was an external USB3 hard drive, that gets about 90-100MB/s sequential read/write.

Everything's working fine for me now actually, after that second edit where I added the small SSD and used it specifically for the incomplete folder.