The Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) costs $0.0374/GB while the WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black costs $0.0453/GB. Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) offers 17% better value per gigabyte as of July 2026. Both products are available on BuyPerUnit with prices from Amazon, Best Buy, and Newegg.
Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) vs WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black — Which Is Better Value?
WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black
Specification Comparison
| Spec | Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) | WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black |
|---|---|---|
| Brand | Seagate | Western Digital |
| Capacity | 18TB | 18TB |
| $/GB | $0.0374 | $0.0453 |
| Price | $672.99 | $814.99 |
| Retailer | Newegg | Newegg |
| Category | Hard Drives (HDD) | Hard Drives (HDD) |
| Subcategory | hdd | hdd |
Price Across Retailers
Which Should You Buy?
Based on current pricing data, the Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) offers better value at $0.0374//GB compared to the WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black at $0.0453//GB — that's roughly 17% less per gigabyte.
The best deal for the Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) is $672.99 at Newegg, while the WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black starts at $814.99 at Newegg.
However, price per gigabyte isn't everything — consider factors like warranty, performance specs, brand reliability, and your specific capacity needs. Check each Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) and WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black product page for detailed specifications and price history.
Frequently Asked Questions
Is Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) or WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black a better deal?
As of July 2026, Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) offers better value at $0.0374//GB compared to WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black at $0.0453//GB. That is approximately 17% better value per gigabyte.
What is the price per GB of Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D)?
The Seagate Exos X20 ST18000NM003D 18TB 7200 RPM 256MB Cache SATA 6.0Gb/s 3.5' Internal Hard Drive (ST18000NM003D) is currently priced at $0.0374/GB ($672.99 for 18TB) at Newegg.
Where can I buy WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black for the cheapest price?
The cheapest price for the WD My Book 18TB USB 3.0, Micro-B External Desktop Hard Drive Black is $814.99 at Newegg, which works out to $0.0453/GB.