Recommended Free Tools
Possibly—but the fact that the bay uses one four-pin Molex (LP4) connector does not prove that it can safely power two hard drives. You need the exact models of both HDDs, the bay or backplane’s rated drive count and input capacity, and the power limits of the particular PSU cable and host circuit. The critical figure is usually startup (spin-up) demand on both 5 V and 12 V rails, not idle consumption.
Why “one Molex” is not a capacity rating
LP4 identifies a connector shape and its nominal conductors. It does not specify the capacity of the entire path feeding your drives. That path may include the PSU’s peripheral output, a particular cable harness, an adapter or splitter, a motherboard power circuit, and the bay’s own wiring and electronics. The weakest part sets the practical limit.
A connector carrying power directly from a PSU can therefore have different limits from an identical-looking connector routed through a motherboard. Supermicro makes this distinction explicit for its A1SRi/A1SAi board: its FAQ says, “This depends on how the board is powered.” With 24-pin ATX power, Supermicro lists 10 A at 12 V and 5 V; when the 4-pin 12 V connector supplies the board, it lists 8 A at 12 V and 6 A at 5 V. Those are limits for that named board and configuration, not a universal Molex or peripheral-lead rating.
Spin-up is the load that can make or break the setup
Hard drives can draw substantially more current while starting their motors than after they reach operating speed. Seagate’s product-manual terminology defines spin-up current as the interval from power-on until the spindle reaches operating speed. Use the exact manual for each drive model and its 5 V and 12 V current or power figures; do not substitute a generic “typical HDD wattage.”
#1 Best Overall
- Connect two LP4 peripheral devices (CD/DVD-ROM drives etc) to a single LP4 connector
- Molex Splitter / LP4 Splitter / Molex Y Splitter / 4 pin Molex Adapter / Molex Power Cable / LP4 to Dual LP4
- Power two (LP4 connected) drives
- Free up connections on the power supply by attaching two devices on a single connection
- Compatible with all IDE hard drives
For two drives that start together, add the two models’ requirements rail by rail:
- 5 V total: drive 1 spin-up current plus drive 2 spin-up current, plus any bay or backplane 5 V load.
- 12 V total: drive 1 spin-up current plus drive 2 spin-up current, plus the bay’s 12 V load.
Compare each total with the documented limit of the supply path, leaving headroom for other devices sharing the cable or circuit. A PSU’s total wattage on its label is not enough if one rail, connector, or harness is the bottleneck.
Rank #2
- Connector 1: (1) 4-pin Molex (LP4) Male / Connector 2: (2) 4-pin Molex (LP4) Female
- Split one 5-1/4in power connector into two 5-1/4in power connectors
- Cable has 1 Male plug & 2 Female plugs
- This power cable is 8 inches.
- Compatible with drives that use IDE/EIDE/ATA/PATA/Molex type plugs
Confirm what the bay actually supports
The bay or backplane must be rated for two drives and for the way you plan to power it. A one-drive specification cannot be extrapolated to two drives.
| Documented item | What it establishes | What it does not establish |
|---|---|---|
| StarTech S25SLOTR | One removable 2.5-inch SATA drive; host connections include one LP4 input, SATA data and SATA power. | It does not certify powering two HDDs from one Molex. |
| StarTech SATBP125VP | One 2.5-inch SATA drive with hot-swap capability marked “Yes.” | It provides no two-drive input rating. |
| Your candidate bay/backplane | Only its own manual can establish supported drive count, input rating, rail limits and any staggered-spin-up behavior. | A connector photograph, product title or similar model cannot substitute for that specification. |
Look specifically for a maximum input current or power rating, supported form factors, the number of bays, and whether the electronics add a separate load. If the documentation says only “LP4 input” and does not state two-drive support, treat the configuration as unverified and ask the manufacturer for a written rating.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchPC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Rank #3
- Split one 5-1/4in power connector into three 5-1/4in power connectors
- Connector 1: (1) 4-pin Molex (LP4) Male
- Connector 2: 4-pin Molex (LP4) Female * 3
- Split one 5-1/4in power connector into three 5-1/4in power connectors
- Cable Length: 8 Inchs. Wire: Pure Copper
Check the complete power path
- Identify both HDDs exactly. Record manufacturer, model number and capacity. Open each manufacturer’s power table and copy the spin-up, 5 V and 12 V requirements for that model and revision.
- Identify the bay or backplane. Verify that it supports two drives, your drive form factor and interface, and simultaneous startup. Record every stated input and maximum-current limit.
- Trace the source. Determine whether the LP4 plug is on a direct PSU peripheral harness, a motherboard-powered circuit, or an adapter chain. Note every connector, splitter and device sharing that harness.
- Read the PSU specifications. Check the 5 V and 12 V rail limits and the specific modular-port or cable restrictions. A modular PSU cable must be the cable approved for that PSU; do not mix cables between brands or models.
- Compare rail totals. Add both drives’ spin-up currents and the bay’s own consumption separately for 5 V and 12 V. Compare those sums with the lowest applicable rating in the chain, not merely the PSU’s headline wattage.
- Check operating behavior. Confirm whether the controller or backplane supports hot-swap and whether it offers staggered spin-up. Staggering can reduce the instantaneous peak, but it does not turn an unrated two-drive bay into a rated one.
- Test conservatively if documentation permits. Start with a backed-up system, monitor for drive resets or power faults, and stop if the bay, connector or cable becomes unusually hot. A successful boot is not proof that the design has adequate margin for every startup condition.
What adapters and splitters can—and cannot—do
A Molex-to-SATA adapter changes the connector; it does not create additional 5 V or 12 V capacity. A splitter likewise places more loads on the same upstream conductors. It is acceptable only when the existing PSU lead and the bay’s documented input are already adequate, and when the adapter is correctly wired and mechanically secure.
Do not use a splitter to infer that a one-drive bay supports two drives. The StarTech LP4 example demonstrates that a removable rack can be designed for one drive with an LP4 input; it supplies no evidence for a dual-drive load.
Rank #4
- Connector 1: 1 end 4-pin Molex Male
- Connector 2: 2 ends 4-pin Molex Female
- Quality Connectors: 4-Pin IDE to 2 x IDE
- Use to add extra power outlets to your power supply for connecting IDE hard drives and IDE CD Rom/DVDRW drives Length: 20 cm Premium
- 2 Pack Computer Molex 4 Pin Power Supply Y Splitter Cable - 2 Female to 1 Male Internal Power Extension Cable
Common failure symptoms and their meaning
- Drives disappear during boot or heavy activity: startup voltage may be sagging, a connector may be loose, or the shared rail may be overloaded.
- Repeated clicking or spin-up retries: the drive may be receiving insufficient startup power; stop repeated attempts and verify the rails and connections.
- Only one drive starts: the bay, adapter chain or harness may be one-drive-rated even though the connector fits both loads.
- Hot plugs, browning plastic or a hot cable: disconnect power immediately and replace the suspect connector or harness; heat indicates an unsafe connection or overload.
- No symptoms but no published rating: absence of a failure is not certification. Obtain the manufacturer’s two-drive rating or choose a bay with one.
When a definitive yes or no is possible
A confident “yes” requires all of the following: the bay explicitly supports two HDDs; its input and maximum current are documented; the summed spin-up demand for your exact drives is below the limiting 5 V and 12 V ratings with margin; and the PSU harness and any motherboard circuit are rated for that load.
A confident “no” applies when any component is one-drive-only, when the rail or harness limit is exceeded, or when the manufacturer forbids the configuration. If the bay’s documentation omits a two-drive rating, the available specifications cannot certify the arrangement—choose a clearly rated two-drive backplane or obtain confirmation from the manufacturer rather than relying on the Molex plug alone.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Quick Recap
Best Value
- Unlock the full potential of your legacy PC build with the Mbiydeg 4 Pin Molex to Dual SATA Power Adapter. This essential connector bridges the gap between older power supply units and modern SATA drives, allowing you to easily add extra hard drives, SSDs, or optical drives without a costly PSU upgrade. Perfect for system builders and tech enthusiasts, the robust sata power cable splitter ensures reliable power delivery from a single 4-pin Molex to two SATA devices. Its plug-and-play installation makes it indispensable for desktop upgrades and custom PC projects, maximizing your existing hardware's utility with simplicity and efficiency.
- Engineered for superior durability and stable performance, our adapter features high-precision connectors and premium copper conductors in a tough PVC jacket. This guarantees minimal voltage drop and consistent power flow, protecting sensitive SATA drives from damage due to power fluctuations. The sata power cable ends have secure latching interfaces to prevent accidental disconnections, ensuring your drives remain powered during extended use. Trust in a product built to last, offering peace of mind for your valuable storage investments in any computing setup.
- Experience broad compatibility that seamlessly integrates with a wide array of devices. This versatile sata power cable adapter converts a standard 4-pin Molex from your PSU into two dedicated SATA power connectors. It is universally compatible with 3.5-inch and 2.5-inch SATA HDDs, SSDs, and SATA optical drives. Whether refurbishing an older workstation, upgrading a gaming rig, or adding storage to a server, this adapter delivers the hassle-free connectivity solution you need for efficient hardware expansion.
- Designed for user convenience and safety, the adapter supports true plug-and-play functionality—no drivers or external power needed. The compact design allows for easy cable management within your computer case, improving airflow. Each sata power cable output is rated to safely handle the power requirements of modern SATA devices. This practical, safe design makes it an excellent choice for both novice DIYers and experienced technicians seeking a reliable way to power multiple drives from a single source.
- Ideal for multiple scenarios, from home office upgrades to advanced gaming system builds. This Mbiydeg power splitter is your go-to solution for expanding storage in desktops, enhancing NAS arrays, or powering drives in external enclosures. Its reliability also makes it perfect for repair shops, labs, and PC maintenance. By choosing this adapter, you're investing in a flexible, cost-effective sata power cable component that extends the life and functionality of your current system, saving time and money on hardware overhauls.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
