Hard Drive slowing to a crawl

About a month or so ago I built a new PC for myself, I currently have an SSD that I had as a secondary drive in my previous PC as the main C: drive, a brand new 3TB Toshiba HDD as my E: drive and the main drive of my previous PC as F:

The brand new 3TB Toshiba HDD has slown to a crawl on both read and write access. Currently I have 296GiB/2.72TiB used up, so masses of free space.

After ruing Crystal Disk Mark on the drive I got 1MB/s read and 0.8MB/s write speed.

Crystal Disk Info has given me this diagnostics info and says that the status of all drives is good.

-- Controller Map ----------------------------------------------------------

• Standard SATA AHCI Controller [ATA]
  • SAMSUNG HD103SI
• Standard SATA AHCI Controller [ATA]
  • TSSTcorp CDDVDW SH-222AB
  • SanDisk SDSSDHII480G
  • TOSHIBA DT01ACA300
• Microsoft Storage Spaces Controller [SCSI]

-- Disk List ---------------------------------------------------------------

1. SanDisk SDSSDHII480G : 480.1 GB [0/0/0, pd1] - sd
2. TOSHIBA DT01ACA300 : 3000.5 GB [1/0/0, pd1]
3. SAMSUNG HD103SI : 1000.2 GB [2/1/0, pd1]

...

(2) TOSHIBA DT01ACA300

       Model : TOSHIBA DT01ACA300
    Firmware : MX6OABB0

Serial Number : 46R4NWHAS Disk Size : 3000.5 GB (8.4/137.4/3000.5/3000.5) Buffer Size : Unknown Queue Depth : 32 # of Sectors : 5860533168 Rotation Rate : 7200 RPM Interface : Serial ATA Major Version : ATA8-ACS Minor Version : ATA8-ACS version 4 Transfer Mode : SATA/600 | SATA/600 Power On Hours : 152 hours Power On Count : 39 count Temperature : 32 C (89 F) Health Status : Good Features : S.M.A.R.T., APM, 48bit LBA, NCQ APM Level : 0000h [OFF] AAM Level : ---- Drive Letter : E:

I am ruing Windows 10, my PSU is 630W, so that shouldn't be an issue. Any ideas as to why it's ruing so slowly and if I can do anything about it?