The Lekuo PB65MX3 puts a B650 chipset on an expansion card to add storage and USB without motherboard bifurcation. Its many connectors share a PCIe 4.0 x4 host link, so they do not each get the card’s full aggregate bandwidth.
The specification that changes the buying decision
The manufacturer’s product page lists four NVMe M.2 slots, four SATA ports and four USB ports. It distinguishes the front M.2 pair, capable of x4 links when used alone, from the rear pair at x2. With all four M.2 slots occupied, all run at x2. The upstream connection remains x4 in every case.
The onboard chipset handles fan-out, so the card does not require the motherboard to split a slot into four independent links. That solves a connectivity requirement, not the bandwidth limit in the diagram.
Work out where contention occurs
Four lanes at 16 GT/s with 128b/130b encoding yield about 16 × 4 × 128 / 130 / 8 = 7.88 GB/s per direction before transaction overhead. This is a calculated link ceiling, not our measured file-copy rate.
Suppose two drives each request a sustained 5 GB/s transfer toward the host. Their combined 10 GB/s demand already exceeds that ceiling, before SATA or USB traffic. Those rates are an illustrative workload, not a promise about any SSD. More connectors can still be useful when devices are used intermittently or the workload is limited by something else.
Check the host as well as the card
Read the motherboard’s slot table. A physically long x16 connector may be wired with fewer lanes, share resources with another slot, or run at an older PCIe generation. The host can therefore impose a lower ceiling than the card.
Also verify case clearance, SSD mounting positions, airflow and the manufacturer’s power instructions. M.2 form factor alone does not prove protocol compatibility; this card’s M.2 sockets are for NVMe, not M.2 SATA drives. Check the exact operating system and devices with the seller, especially for configurations outside mainstream desktop Linux or Windows.
We have not tested this card. A familiar chipset is a useful compatibility clue, but not evidence that every port, power state or workload will work on every system. For a capacity expansion with occasional transfers, the design is worth considering. For several SSDs sustaining maximum throughput at once, compare platforms with more host lanes before treating this fan-out card as an upgrade in aggregate speed.
Source
- Lekuo PB65MX3 specification and slot allocation
- Bandwidth and two-drive example are explicit calculations, not product benchmarks.
Checked the manufacturer’s lane allocation; removed universal driver and no-performance-cost claims, and separated port count from shared host bandwidth.