Replacement for 251974-B21: Drop-In Alternatives We Stock
Looking for a replacement for the 251974-B21 (251974-B21 - Compaq 20 GB 3.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 2 MB Buffer)? 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 251974-B21
| SKU | 251974-B21 |
|---|---|
| Product | 251974-B21 - Compaq 20 GB 3.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 2 MB Buffer |
| Current price | $213.26 |
| Stock status | In Stock |
| Detail page | View 251974-B21 › |
Drop-in replacements for 251974-B21
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.
201066-B21 - Compaq 40 GB 3.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 128 KB Buffer
SKU: 201066-B21
Price: $144.58
250020-B21 - Compaq 80 GB 3.5 Internal Hard Drive - 1 Pack - OEM - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 2 MB Buffer
SKU: 250020-B21
Price: $182.93
191189-B21 - Compaq 36.20 GB 3.5 Internal Hard Drive - 1 Pack - Ultra320 SCSI - 10000 rpm
SKU: 191189-B21
Price: $335.86
310504-B21 - Compaq 73 GB 3.5 Internal Hard Drive - 1 Pack - Ultra320 SCSI - 10000 rpm
SKU: 310504-B21
Price: $617.50
MHT2060AH - Toshiba Mobile MHT-AH 60 GB 2.5 Internal Hard Drive - 1 Pack IDE Ultra ATA/100 (ATA-6) - 5400 rpm - 8 MB Buffer
SKU: MHT2060AH
Price: $128.84
HDD2168 - Toshiba HDD MK2018GAS 20 GB 2.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 4200 rpm - 2 MB Buffer
SKU: HDD2168
Price: $157.07
HDD2146 - Toshiba MK6015MAP 6 GB 2.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/66 (ATA-5) - 4200 rpm - 256 KB Buffer
SKU: HDD2146
Price: $158.59
22P7157 - IBM 40 GB 3.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 2 MB Buffer
SKU: 22P7157
Price: $165.79
91.AB033.031 - Acer 91.AB033.031 40 GB 3.5 Internal Hard Drive - 1 Pack - IDE Ultra ATA/100 (ATA-6) - 7200 rpm
SKU: 91.AB033.031
Price: $168.93
07N9219 - IBM 120 GB 3.5 Internal Hard Drive - 20 Pack - OEM - IDE Ultra ATA/100 (ATA-6) - 7200 rpm - 2 MB Buffer
SKU: 07N9219
Price: $182.37
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.