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Key takeaways
- SATA is 6Gb/s per the SATA-IO. SAS-3 is 12Gb/s and 24G SAS signals at 22.5 Gbaud, per the SCSI Trade Association roadmap.
- Seagate says SATA drives may be plugged into SAS controllers and SAS drives cannot be plugged into SATA controllers.
- Seagate sells the Exos X24 as SATA and as SAS. On the Seagate data sheet the capacities, 7,200 RPM, 285MB/s sustained rate, MTBF, AFR and read error rating are identical. The ports, interface rate and power draw differ.
- In the Memory Clearance catalogue on 17 October 2026, refurbished 7,200 RPM SAS hard drives had a lower median price than SATA at 1TB, 2TB, 3TB, 4TB and 6TB, by 11.0% to 32.1%. Refurbished SAS SSDs had a higher median at 7 of 9 capacities.
- Seagate lists a 1 in 10^16 error rating for its 10K and 15K SAS drives. It is a property of those drives, not of SAS itself.
Short answer: SAS has the higher interface rate and dual ports, and SATA is 6Gb/s with a single port. A SATA drive works on a SAS controller and backplane, and a SAS drive does not work on a SATA controller. Which one costs less depends on the capacity, as the tables below show.
SAS vs SATA at a glance
- Speed. SATA Revision 3.0 defines 6Gb/s. The SCSI Trade Association roadmap lists 6Gb/s for SAS-2 and 12Gb/s for SAS-3. The same roadmap lists 24G SAS at 22.5 Gbaud.
- Ports. Seagate states that SAS provides dual porting as standard, so if one port goes down a second port is available for failover. In the Exos X24 data sheet, the SATA models are single port and the SAS models are dual port.
- Compatibility. Seagate states SATA drives may be plugged into SAS controllers, and SAS drives cannot be plugged into SATA controllers. The SATA specification describes a SAS domain attaching to unmodified SATA devices using the Serial ATA Tunneled Protocol.
- Direction of data. Dell states that SATA channels move data in only one direction at a time, while on SAS reads and writes can travel at the same time.
- Queue depth. The SATA specification tracks up to 32 outstanding commands with Native Command Queuing. Seagate's SAS manuals list a 128 deep task set for the Exos X24 SAS and the same for the Exos 15E900. We do not give a single SAS queue depth, because no SAS standard figure is in our sources.
The same drive in both versions: Seagate Exos X24
Seagate sells the Exos X24 as a SATA 6Gb/s drive and as a SAS 12Gb/s drive, and publishes both in one data sheet. That makes a clean comparison: same drive family, same spindle speed, different interface.
| Exos X24 spec | SATA 6Gb/s | SAS 12Gb/s | Source |
|---|---|---|---|
| Differs: interface rate | 6Gb/s | 12Gb/s | Seagate Exos X24 data sheet |
| Differs: interface ports | Single | Dual | Seagate Exos X24 data sheet |
| Differs: idle power, average | 6.3 W | 6.5 W | Seagate Exos X24 data sheet |
| Differs: max operating power, random read and write 4K/16Q | 8.9 W and 7.1 W | 9.8 W and 8.2 W | Seagate Exos X24 data sheet |
| Differs: sector sizes | 512 and 4096 | 512, 520, 528, 4096, 4160 and 4224 | Seagate Exos X24 data sheet |
| Differs: FIPS model | None listed | One SED-FIPS2 model listed | Seagate Exos X24 data sheet |
| Same: capacities | 12TB, 16TB, 20TB, 24TB | 12TB, 16TB, 20TB, 24TB | Seagate Exos X24 data sheet |
| Same: spindle speed | 7,200 RPM | 7,200 RPM | Seagate Exos X24 data sheet |
| Same: max sustained transfer rate | 285MB/s | 285MB/s | Seagate Exos X24 data sheet |
| Same: random read and write 4K QD16 IOPS | 168 and 550 | 168 and 550 | Seagate Exos X24 data sheet |
| Same: MTBF | 2,500,000 hours | 2,500,000 hours | Seagate Exos X24 data sheet |
| Same: AFR at full 24x7 operation | 0.35% | 0.35% | Seagate Exos X24 data sheet |
| Same: nonrecoverable read errors per bits read | Less than 1 in 10^15 | Less than 1 in 10^15 | Seagate Exos X24 data sheet |
On the same drive, Seagate rates the reliability figures identically for SATA and SAS. The interface is what differs: rate, ports, sector options and power draw.
The 1 in 10^16 error rating belongs to specific drives, not to the SAS interface. Seagate's Exos 10E2400, a 10,000 RPM SAS drive, and its Exos 15E900, a 15K SAS drive, each list 1 per 10^16 bits read as the maximum. Their data sheets are from 2018 and 2017, and we did not check whether those models are still current. The 7,200 RPM Exos X24 is rated at less than 1 in 10^15 on both interfaces. Do not read a better error rate as a property of SAS by itself.
What SAS and SATA cost in our catalogue
In the Memory Clearance catalogue on 17 October 2026, the Server Hard Drives category had 25,259 SAS listings, of which 7,146 were priced and in stock, and 4,422 SATA listings, of which 1,386 were priced and in stock. The Solid State Drives category had 8,833 SAS listings (3,259 priced and in stock) and 15,644 SATA listings (3,253 priced and in stock). The two tables below compare refurbished listings only, so the new against refurbished mix cannot drive the gap. A row needs at least 20 priced listings on each side.
Refurbished SSDs: median price by capacity, 17 October 2026
| Capacity | SAS median | SAS priced listings | SATA median | SATA priced listings | SAS against SATA |
|---|---|---|---|---|---|
| 200GB | $153 | 104 | $153 | 73 | level (0.0%) |
| 400GB | $269 | 232 | $193 | 45 | 39.5% above SATA |
| 480GB | $384 | 80 | $277 | 332 | 38.6% above SATA |
| 800GB | $414 | 333 | $269 | 90 | 53.7% above SATA |
| 960GB | $562 | 227 | $493 | 301 | 14.1% above SATA |
| 1.6TB | $691 | 148 | $371 | 49 | 86.1% above SATA |
| 1.92TB | $738 | 295 | $651 | 299 | 13.2% above SATA |
| 3.84TB | $1,018 | 328 | $1,049 | 208 | 3.0% below SATA |
| 7.68TB | $3,064 | 169 | $2,820 | 31 | 8.7% above SATA |
In the Memory Clearance catalogue on 17 October 2026, refurbished SAS SSDs had a higher median price than SATA at 7 of 9 capacities: 400GB, 480GB, 800GB, 960GB, 1.6TB, 1.92TB and 7.68TB. The 200GB medians were level at $153. At 3.84TB the SAS median of $1,018 was 3.0% below the SATA median of $1,049.
Refurbished 7,200 RPM hard drives: median price by capacity, 17 October 2026
| Capacity | SAS median | SAS priced listings | SATA median | SATA priced listings | SAS against SATA |
|---|---|---|---|---|---|
| 500GB | $137 | 53 | $104 | 122 | 31.4% above SATA |
| 1TB | $121 | 282 | $147 | 138 | 17.6% below SATA |
| 2TB | $160 | 385 | $223 | 156 | 28.0% below SATA |
| 3TB | $150 | 150 | $180 | 42 | 16.3% below SATA |
| 4TB | $188 | 273 | $277 | 47 | 32.1% below SATA |
| 6TB | $240 | 177 | $269 | 34 | 11.0% below SATA |
| 8TB | $434 | 143 | $438 | 26 | 0.9% below SATA |
| 10TB | $414 | 57 | $418 | 33 | 0.9% below SATA |
| 12TB | $554 | 56 | $517 | 35 | 7.3% above SATA |
In the Memory Clearance catalogue on 17 October 2026, refurbished 7,200 RPM SAS hard drives had a median price 11.0% to 32.1% below SATA at 1TB, 2TB, 3TB, 4TB and 6TB. At 8TB and 10TB the two were within 0.9% of each other. At 12TB SAS was 7.3% above SATA, and at 500GB it was 31.4% above. So SAS is not always the expensive option. We have no source that explains why the prices differ, so we do not offer a reason.
Where each one fits
- Dual port and failover. If a design needs a second path to the drive, SAS is the interface that has it as standard, per Seagate. Seagate also states that a SATA drive on a SAS port needs an interposer to get dual port or multi-host capability.
- 10K and 15K drives. Seagate's Exos 10E2400 is a 10,000 RPM drive with a 12Gb/s SAS interface, and its Exos 15E900 is a 15K drive with a 12Gb/s SAS interface. That is two Seagate product lines, not a rule for every maker. In the Memory Clearance catalogue on 17 October 2026, priced and in-stock hard drive listings stating 10,000 RPM numbered 1,971 SAS and 8 SATA, and listings stating 15,000 RPM numbered 1,302 SAS and 1 SATA. Browse the 10K RPM and 15K RPM collections.
- Cable reach. The SATA specification defines internal 6.0 Gbit/s cabling up to 1 m. The SCSI Trade Association recommends external SAS cables up to 6 meters (passive copper), 20 meters (active copper) and 100 meters (optical), and internal SAS passive copper up to 1.5 meters.
- Mixing SATA into a SAS system. Seagate's Exos X24 SAS manual says SAS connectors, cables and electrical interface are compatible with SATA, giving the choice of populating a system with either SAS or SATA drives. The T10 working draft shows a SATA drive plug attaching to a SAS backplane receptacle.
- Newer SAS. Microchip lists 24G SAS as backward compatible with SAS-3, SAS-2 and SATA.
NVMe is a different interface. NVM Express describes it as the register interface and command set for PCI Express attached storage, so NVMe drives connect over PCIe. Browse our NVMe SSD collection.
How to choose
- Check what your controller supports. A SAS controller accepts SATA drives, and a SATA controller does not accept SAS drives, per Seagate.
- Check your backplane the same way. The T10 working draft shows a SATA drive plug attaching to a SAS backplane receptacle; before buying SAS drives, confirm that your backplane is SAS.
- Decide whether you need two ports on each drive. Seagate states that SAS supports dual porting as standard, and in the Exos X24 data sheet the SATA models are single port and the SAS models are dual port.
- Compare SAS and SATA prices at the capacity you need, using the tables above, not a general rule.
- If you are unsure whether you need a RAID controller or a host bus adapter, read our RAID controller vs HBA guide.
Method: active listings in the Server Hard Drives and Solid State Drives categories whose name states SAS or SATA (not both) and a capacity. Interface, capacity and spindle speed are read from the listing name. Medians use listings whose price is shown online, above zero and marked in stock, on 17 October 2026 vendor prices. Like-for-like rows compare refurbished listings only, so the new against refurbished mix cannot drive the gap, and need at least 20 priced listings on each side. Hard drive rows compare 7,200 RPM drives only. Counts on 17 October 2026: 25,259 SAS and 4,422 SATA hard drive listings, 8,833 SAS and 15,644 SATA SSD listings.