Wow, you've opened a can of worms.
The short answer is that one is a native WD model, the other is a native HGST model. The HGST model comes in two flavours, one with 8 heads, the other with 10 heads. The WD model has 8 heads.
The long story:
I found two versions of the WD6003FZBX -- WD6003FZBX-
00K5WB0 and WD6003FZBX-
00GXAB0. These are from two different families,
WDVL6 and
WDVL8. Both drives are based on HGST's firmware architecture, and both have a WWN that begins with
5000CCA. One has 8 heads, the other has 10.
https://en.wikipedia.org/wiki/World_Wide_Name
This info comes from WD's warranty checker:
https://support-en.wd.com/app/warrantystatusweb
Code:
Serial Number Warranty Status Model Number Description Warranty Expiration Date*
V8KG6NXR IN LIMITED WARRANTY WD6003FZBX-00K5WB0 WDVL6 7200 256M SATA3 6GB/S 6.0 TB 8HD STD HGST 20-Mar-2025
V8KGSNXR IN LIMITED WARRANTY WD6003FZBX-00K5WB0 WDVL6 7200 256M SATA3 6GB/S 6.0 TB 8HD STD HGST 24-Mar-2025
VAJVNNYL IN LIMITED WARRANTY WD6003FZBX-00GXAB0 WDVL8 7200 256M SATA3 6GB/S 6.0 TB 10HD STD HGST 21-Dec-2024
PC HA710
R/N US7SAN8T0
WWN 5000CCA099E84E45
Two examples:
https://image.made-in-china.com/155...pm-Internal-Hard-Drive-Wd6003fzbx-SSD-HDD.jpg
https://i.ebayimg.com/images/g/sKMAAOSwQRNg~aS9/s-l1600.jpg
The WD6004FZWX-
00BKVA0 belongs to the
AvalonC family. It has native WD firmware architecture. The PCB is a WD PCB, 2060-810032. It is labelled as a "gaming hard drive". It has 8 heads. The WWN begins with
50014EE.
Code:
Serial Number Warranty Status Model Number Description Warranty Expiration Date*
AD01YR6L IN LIMITED WARRANTY WD6004FZWX-00BKVA0 AVALONC 7200 128M SATA3 6GB/S 6.0 TB 8HD STD 8-Dec-2027
PC HA710
R/N 810032
gaming HDD
WWN 50014EE26A66E483
Here is one example:
https://scontent.fsyd4-1.fna.fbcdn....i_EIUWuL5mP287N6WtB7s56_NZGFZ-hEg&oe=64057204