Replacement for CTD421SR4G: Drop-In Alternatives We Stock
Looking for a replacement for the CTD421SR4G (CTD421SR4G - Crucial 4GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module)? Pro Disk Network ships Crucial 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 CTD421SR4G
| SKU | CTD421SR4G |
|---|---|
| Product | CTD421SR4G - Crucial 4GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module |
| Current price | $82.17 |
| Stock status | In Stock |
| Detail page | View CTD421SR4G › |
Drop-in replacements for CTD421SR4G
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.
CT4G4RFS8213.9FA2 - Crucial Technology 4GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CT4G4RFS8213.9FA2
Price: $82.17
CT4G4RFS8213 - Crucial Technology 4GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CT4G4RFS8213
Price: $82.17
CT2K4G4RFS8213 - Crucial 8GB Kit (2 X 4GB) DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory
SKU: CT2K4G4RFS8213
Price: $156.13
CT4K4G4RFS8213 - Crucial Technology 16GB Kit (4 X 4GB) DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory
SKU: CT4K4G4RFS8213
Price: $304.05
CT8G4RF84213.18FA2 - Crucial 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CT8G4RF84213.18FA2
Price: $85.92
CT8G4RFS4213ES - Crucial 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CT8G4RFS4213ES
Price: $85.92
CT8G4RFS4213ES.18FDA2 - Crucial 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CT8G4RFS4213ES.18FDA2
Price: $85.92
CTD421SR8G - Crucial 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Single Rank Memory Module
SKU: CTD421SR8G
Price: $85.92
CTD421R16G - Crucial 16GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Dual Rank Memory Module
SKU: CTD421R16G
Price: $93.37
CT16G4VFD4213.18DA1 - Crucial Technology 16GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Dual Rank Memory Module
SKU: CT16G4VFD4213.18DA1
Price: $93.37
CT8G4RFD8213 - Crucial Technology 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Dual Rank Memory Module
SKU: CT8G4RFD8213
Price: $97.12
CT8G4RFD8213.18FA1 - Crucial 8GB DDR4-2133MHz PC4-17000 ECC Registered CL15 288-Pin DIMM 1.2V Dual Rank Memory Module
SKU: CT8G4RFD8213.18FA1
Price: $97.12
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.