Replacement for DS420J-4TB-RED: Drop-In Alternatives We Stock
Looking for a replacement for the DS420J-4TB-RED (Synology DS420J/4TB-RED DS420j 4TB 4-bay NAS)? Pro Disk Network ships drop-in replacements and equivalent modern parts from US inventory. Every alternate below is in-stock today with same-day shipping for orders placed before 2pm ET. If your unit is still under warranty, contact our engineering team — we offer cross-shipping for B2B customers on Net 30 terms.
About the DS420J-4TB-RED
| SKU | DS420J-4TB-RED |
|---|---|
| Product | Synology DS420J/4TB-RED DS420j 4TB 4-bay NAS |
| Stock status | In Stock |
| Detail page | View DS420J-4TB-RED › |
Drop-in replacements for DS420J-4TB-RED
Each part below is currently in our US warehouse, ships same-day for orders before 2pm ET, and includes our 90-day warranty. SKUs link to the full product page with photos, datasheets and B2B quote form.
SA3400 Synology SA3400 Highly scalable NAS equipped with an 8-core CPU and 16GB ECC RDIMM memory(Highly scalable NAS meeting extensive data storage needs)
SKU: SA3400
Price: $18,829.47
STDD8000100 - Seagate NAS Pro 2-Bay 8TB (2 x 4TB) USB 3.0 Ethernet NAS Server
SKU: STDD8000100
Price: $1,281.45
STCT8000100 - Seagate NAS 2-bay 8TB (2 x 4TB) USB 3.0 Ethernet NAS Server
SKU: STCT8000100
Price: $2,160.53
WD40EFZX - Western Digital Red Plus NAS 4TB 5400RPM SATA 6Gb/s 128MB Cache 3.5-inch Hard Drive
SKU: WD40EFZX
Price: $294.74
WD40EFAX - Western Digital Red NAS 4TB 5400RPM SATA 6Gb/s 256MB Cache 3.5-inch Hard Drive
SKU: WD40EFAX
Price: $318.32
WD4003FFBX-68MU3N0 - Western Digital Red Pro NAS 4TB 7200RPM SATA 6Gbps 256MB Cache 3.5-inch Hard Drive
SKU: WD4003FFBX-68MU3N0
Price: $380.04
WD4003FFBX - Western Digital Red Pro NAS 4TB 7200RPM SATA 6Gbps 256MB Cache 3.5-inch Hard Drive
SKU: WD4003FFBX
Price: $382.59
WDS400T1R0A - Western Digital Red SA500 4TB NAS Triple-Level Cell SATA 6Gb/s 3D NAND 2.5-inch Solid State Drive
SKU: WDS400T1R0A
Price: $1,008.00
Western WDS400T2R0A-68CKB0 Western Digital WDS400T2R0A-68CKB0 Red SA500 4TB SATA 6Gb/s 2.5-inch NAS Internal Solid State Drive
SKU: WDS400T2R0A-68CKB0
Price: $1,984.21
How we pick replacements
Every recommendation above was selected using these criteria:
- Drop-in compatibility — same form factor (2.5"/3.5", PCIe slot, SFP port, etc.), so it fits the original chassis without modification
- Equivalent or better performance — matched on RPM/IOPS/speed/throughput, never downgraded
- Same-brand-preferred — we list the OEM-equivalent first when available, then trusted aftermarket
- Warranty coverage — 90-day Pro Disk warranty on every part, with 1-year option for B2B
- In stock today — never recommend a part that is on backorder
Need help confirming compatibility?
Our engineers validate every replacement against your specific server, switch, or chassis model before shipment. Email sales@prodisknetwork.com with your platform model (e.g., Dell PowerEdge R740, HP DL380 Gen10, Cisco Catalyst 9300) and we will confirm the exact part number that drops into your hardware.