Most NAS hard drives under $100 AUD are 2TB or 4TB CMR models from Seagate or WD. Both brands make NAS-specific drives with vibration compensation and TLER (Time Limited Error Recovery). Features that prevent drives from dropping out of a RAID array during a slow read. At the sub-$100 price point, the Seagate IronWolf and WD Red Plus are the two drives worth buying. This guide compares both with current AU pricing so you know exactly what you are getting.
In short: For a single drive under $100, the Seagate IronWolf 4TB (~$95-$99) is the best value. For 2TB, the WD Red Plus 2TB (~$79-$89) and IronWolf 2TB (~$75-$85) are similarly priced. Either works. All drives below are CMR. Avoid the standard WD Red which uses SMR.
Why Buy a NAS-Specific Drive?
Desktop hard drives are not designed for 24/7 NAS operation. NAS drives differ in three meaningful ways: TLER (Time Limited Error Recovery), which caps the time a drive spends recovering a bad sector so it does not get ejected from a RAID array; rotational vibration compensation, which matters when multiple drives spin in the same chassis; and workload ratings, typically 180TB/year for entry NAS drives vs 55TB/year for desktop drives.
At the sub-$100 price point, the NAS-specific premium over a desktop drive is only $10-$20 AUD. It is worth paying. For a deeper comparison of NAS drive options at all capacities, see our Best NAS Hard Drives Australia guide.
Seagate IronWolf. AU Pricing and Specs
The Seagate IronWolf is Synology-tested and QNAP-certified, making it a safe default for most NAS buyers in Australia. At the sub-$100 price point, the 2TB and 4TB IronWolf are the two relevant models.
Seagate IronWolf. Under $100 AUD Models
| IronWolf 2TB | IronWolf 4TB | |
|---|---|---|
| Model code | ST2000VN003 | ST4000VN006 |
| RPM | 5400 RPM | 5900 RPM |
| Recording type | CMR | CMR |
| Cache | 64MB | 256MB |
| Workload rating | 180TB/year | 180TB/year |
| TLER | Yes | Yes |
| RV sensors | Yes | Yes |
| AU price (Mwave / PLE) | ~$75-$85 | ~$95-$99 |
| Warranty | 3 years | 3 years |
The 4TB IronWolf at ~$95-$99 is the standout value: $100 per drive buys you RAID 1 with 4TB usable in a 2-bay NAS, or RAID 5 protection with 8TB usable across a 4-bay. The 5900 RPM spin speed and 256MB cache give slightly better sequential throughput than the 2TB model. Relevant for Plex libraries and video editing scratch storage. IronWolf drives are stocked by Mwave, PLE, Scorptec, and UMart across Australia with local 3-year warranty.
WD Red Plus. AU Pricing and Specs
WD Red Plus is the CMR-only line from Western Digital's NAS drive range. Distinct from the original WD Red, which includes SMR models at lower capacities. At the sub-$100 price point, the 2TB and 4TB WD Red Plus are the relevant options.
WD Red vs WD Red Plus: The standard WD Red uses SMR (Shingled Magnetic Recording) at 1TB and 2TB. SMR drives perform poorly in RAID arrays under sustained write load. Always buy WD Red Plus (CMR) for NAS use. Check the exact model code. WD Red Plus 2TB is WD20EFPX.
WD Red Plus. Under $100 AUD Models
| WD Red Plus 2TB | WD Red Plus 4TB | |
|---|---|---|
| Model code | WD20EFPX | WD40EFPX |
| RPM | 5400 RPM | 5400 RPM |
| Recording type | CMR | CMR |
| Cache | 64MB | 128MB |
| Workload rating | 180TB/year | 180TB/year |
| TLER | Yes | Yes |
| RV sensors | Yes (2-bay+) | Yes (2-bay+) |
| AU price (Mwave / PLE) | ~$79-$89 | ~$95-$105 |
| Warranty | 3 years | 3 years |
The WD Red Plus 4TB often sits at $99-$105. Just over the $100 threshold depending on retailer and week. Watch for sales at Mwave and PLE that regularly bring it under $100. The 2TB Red Plus is solidly priced and a good option for 2-bay home NAS users who want 2TB raw per drive with RAID 1 protection.
IronWolf vs WD Red Plus. Which to Choose?
At this price point, both drives perform similarly in real NAS use. The meaningful differences are small:
Pros
- IronWolf 4TB: 5900 RPM and 256MB cache give slightly faster sequential reads than Red Plus 4TB at 5400 RPM/128MB cache
- IronWolf includes IronWolf Health Management. A Synology DSM integration for drive health monitoring
- IronWolf is slightly more widely stocked across AU retailers
Cons
- IronWolf 2TB spins at 5400 RPM (same as Red Plus). No advantage at this capacity
- WD Red Plus is sometimes cheaper during sales at Mwave and PLE. Check both before buying
- WD drives may suit QNAP users who prefer WD's NAS certification programme
For most buyers: buy whichever is cheaper on the day. Both are CMR, both have TLER and RV compensation, and both carry a 3-year warranty with local AU support. If the IronWolf 4TB is at $95 and the WD Red Plus 4TB is at $105, buy the IronWolf. If prices are equal, the IronWolf gets a marginal nod for the 5900 RPM / 256MB cache advantage at 4TB.
What to Avoid. SMR Drives in NAS
Several drives appear cheap at the sub-$80 mark but use SMR (Shingled Magnetic Recording). SMR drives use overlapping tracks to fit more data on a platter, but they require a cache flush under sustained sequential writes. Causing severe write speed degradation in RAID rebuild scenarios. This can extend a RAID 5 rebuild from hours to days and dramatically increases the risk of a second drive failure completing. Drives to avoid in NAS:
- WD Red (non-Plus) 1TB and 2TB. SMR, clearly labelled but easy to confuse with Red Plus
- Seagate Barracuda (any capacity). Desktop drive, no TLER
- WD Blue. Desktop drive, no TLER
- Generic no-name drives at unusually low prices. No NAS certification, no TLER
For a full explanation of CMR vs SMR and why it matters in a RAID array, see our NAS RAID Explained guide.
How Many Drives and What Capacity?
Budget matters when buying multiple drives. At $100 per drive:
- 2-bay NAS with RAID 1: 2 × 4TB IronWolf = ~$190-$200, giving 4TB usable with full redundancy
- 4-bay NAS with RAID 5: 4 × 4TB IronWolf = ~$380-$400, giving 12TB usable with single-drive fault tolerance
- 4-bay NAS with RAID 6: 4 × 4TB IronWolf = same cost, giving 8TB usable with dual-drive fault tolerance
For capacity planning and RAID configuration help, use our RAID Calculator. To estimate how long a RAID rebuild takes with these drives, see the RAID Rebuild Time Estimator.
Where to Buy NAS Drives Under $100 in Australia
Mwave and PLE Computers consistently offer the best drive pricing in Australia. Scorptec and UMart are also competitive. All four retailers stock IronWolf and WD Red Plus with local AU warranty and ship nationally. Watch for weekly specials. Both the IronWolf 4TB and WD Red Plus 4TB appear on sale at $89-$95 several times per year. For the full retailer breakdown, see Where to Buy a NAS in Australia.
Related reading: our NAS buyer's guide.
Free tools: NAS Sizing Wizard and Drive Failure Risk Calculator — no signup required.
Is the Seagate IronWolf 4TB under $100 in Australia?
Yes. The IronWolf 4TB (ST4000VN006) is typically priced at $95-$99 AUD from Mwave and PLE. It occasionally drops below $90 during sales. Street prices fluctuate so check current pricing before buying.
Can I use WD Red (not Red Plus) in a NAS?
Technically yes, but it is not recommended. The standard WD Red uses SMR recording at 1TB and 2TB capacities, which performs poorly during RAID rebuilds. Always buy WD Red Plus (model code WD20EFPX for 2TB, WD40EFPX for 4TB). It uses CMR and is designed for continuous NAS operation.
How many TB do I need in a NAS drive?
For most home users, 4TB per drive is the sweet spot. It sits at the sub-$100 price point and gives meaningful usable storage in RAID 1 (4TB usable from 2 drives) or RAID 5 (12TB usable from 4 drives). Use our RAID Calculator to check exactly how much usable space your configuration provides.
Do NAS drives come with warranty in Australia?
Yes. IronWolf and WD Red Plus both carry a 3-year limited warranty. When purchased from authorised AU retailers (Mwave, PLE, Scorptec, UMart), warranty claims are handled locally under ACL conditions. Grey-import drives purchased from overseas sellers may not qualify for local warranty support.
What is the best NAS drive under $100 for a Synology?
The Seagate IronWolf 4TB is the recommended pick for Synology. It is on Synology's official compatibility list, includes IronWolf Health Management support in DSM, and typically sits at $95-$99 AUD. The WD Red Plus 4TB is an equally valid alternative if priced similarly on the day you buy.
Not sure how many drives or what capacity you need? Use our RAID Calculator to check usable storage for any RAID level and drive combination.
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