Data transfer hang ups from external HDD/ flash drives

Using an old Toshiba Satelite P755-s5263, 6 gigs of RAM, Win 7 Ultimate x64, i5-2410M

I am trying to obtain some music files (~35 gigs worth) from an external HDD (I will call HDD1, 5400 RPM). Music and documents are on a different partition than the system on HDD1.

The music was initially transferred from a different HDD (HDD3) that had win 10 home on it, different license than my win 7 ultimate. I am pretty sure I gave permissions to the license on HDD1/ SSD to access all of the files. HDD3 was failing mechanically, but there were no bad sectors or corrupt data. I prefer win 7, so I originally did a clean install to HDD1 before shortly buying a SSD.

changed from using HDD1 as the only drive to a SSD-HDD combo (HDD2 is in a caddy in the CD drive, 7200 RPM).

cloned SSD from HDD1, clone was successful.

...trying to get music and other documents from the other partition of HDD1 to HDD2 has been a nightmare.

Tried most of the following by either:
a. having HDD1 hooked up via a SATA to 3.0 cable, HDD2 in a caddy in the disc drive, and SSD in primary
b. Having HDD1 in primary slot, HDD2 in caddy
c. tried HDD1 in a SATA enclosure that used a double sided usb cord for transfer.

transfer is initially fast, but goes down to ~5MB/s, then to kb/s. hangs up in the middle of transferring

I have tried:
1. did chkdsk on all HDDs and their partitions, no problems
2. did scannow, no problems
3. did microsoft troubleshooting, did not help
4. did HDtune and crystal disk on both, both are fine*
5. made sure writing was enabled on HDD2
6. tried moving music files from HDD to flash drive using 3.0, still hang ups in the middle of the transfer.
7. tried making a backup of the music files to just transfer the backup and then recover it, eventually it hangs up as well
8. tried transferring small parts of music library, still hang ups
9. tried cloning partition, hang ups.
10. checked to make sure all drivers were updated
11. checked to see that I still had permission to access everything (not 100%).

*HDD1 avg read/write 60/50 MB/s
*HDD2 avg read/write 100/5 MB/s even with writing enabled???

Thank you if you actually read all of that, I am not sure if HDD2 is going bad (it shouldnt, its new....) or if there is some other feature I am not enabling that will speed data transfer up as well.

Again, data transfer was still slow/ hung up while trying to transfer music files to a flash drive in the 2.0 or 3.0 slots.

Any advice is MUCH appreciated!!

I think I just discovered what may be really going on, HDD1 is probably just going through mechanical failure...

I am not hearing any weird noises or anything, but Event Viewer showed many "Event 7 - The device, \Device\Harddisk2\DR2, has a bad block".

well, there goes $300 for recovery. I did crystal disk again, and it says "caution" now.