Both cards put 12Gb/s SAS on a single PCIe 3.0 x8 link. The 9300-16i has four SFF-8643 connectors for up to 16 drives; the 9300-8i has two for 8. Pick by bay count, cable routing and drive type, not by the speed printed on the box, because the host link caps both of them.
Ports, Connectors and Cable Count
Every card in the 9300 family sits on the same host interface and speaks the same 12Gb/s SAS signalling. What changes between models is how many ports it exposes and how those ports leave the board. One SFF-8643 connector (mini-SAS HD) carries four SAS lanes, so port count and connector count are tied together in a fixed ratio.
| Card | Ports | Connectors | Drives direct | Host link | NVMe |
|---|---|---|---|---|---|
| 9300-4i | 4 internal | 1x SFF-8643 | 4 | PCIe 3.0 x8 | No |
| 9300-8i | 8 internal | 2x SFF-8643 | 8 | PCIe 3.0 x8 | No |
| 9300-16i | 16 internal | 4x SFF-8643 | 16 | PCIe 3.0 x8 | No |
| 9300-8e | 8 external | 2x SFF-8644 | 8 per enclosure | PCIe 3.0 x8 | No |
| 9400-8i | 8 internal | 2x SFF-8643 | 8 | PCIe 3.1 x8 | Yes |
| 9500-16i | 16 internal | 4x SFF-8643 | 16 | PCIe 4.0 x8 | Yes |
Cable choice is where most builds stall. A 9300-16i needs four breakout cables if you are wiring drives directly: SFF-8643 to 4x SFF-8482 for SAS or SATA drives in caddies, or SFF-8643 to 4x SATA fan-out if you are only running SATA. If your chassis has a backplane, you need one cable per backplane connector instead, and the backplane end may be SFF-8643 or the older SFF-8087, which needs a different cable.
The 9300-8i is the same silicon with half the ports: two connectors, eight drives, two cables, and it fits in builds where the chassis tops out at eight bays. The small 9300-4i exists for 4-bay boxes and boot mirrors, and the 9300-8e moves those eight ports outside the chassis with SFF-8644 for a disk shelf.
The PCIe 3.0 x8 Ceiling
This is the part buyers miss. A 12Gb/s SAS lane delivers about 1.2 GB/s of usable throughput after encoding. Sixteen lanes add up to roughly 19.2 GB/s of drive-side capacity. The card’s host link, PCIe 3.0 x8, is about 7.9 GB/s of raw bandwidth and closer to 6.5 GB/s once protocol overhead is taken out. The card can therefore never deliver everything its ports can theoretically carry.
In practice that is fine, because drives are far slower than the link:
- 16 SAS hard drives at roughly 200-280 MB/s each is about 3.5-4.5 GB/s in aggregate. That fits inside the x8 link with room to spare, and a 16-bay HDD array on a 9300-16i will saturate the drives long before it saturates the slot.
- 16 SAS SSDs at 800 MB/s and up each is 12-16 GB/s. Here the slot, not the drives, becomes the limit, and a sequential read test levels off near the link ceiling.
- Cache and striping do not change this. A RAID 0 across sixteen SSDs still exits through one x8 link.
So the honest rule is: a 9300-16i is a good 16-drive HDD controller and a mediocre 16-drive SSD controller. If your plan is a flash array, the 9500-16i moves to PCIe 4.0 x8, roughly doubling the link to about 15.8 GB/s, and also handles NVMe. We covered the slot-side trade-off separately in what a 9500-16i loses in a PCIe 3.0 slot.
What the 9300 Series Cannot Do
These are host bus adapters, and that word matters. There is no cache memory on the board, no battery, and no CacheVault supercap, so there is nothing to write back and nothing to age out. If you are coming from a cache-equipped card, read how a dying supercap shows up on a 9361-8i, because that failure mode simply does not exist here.
RAID support is limited by design. In IT mode the card is pure pass-through, which is what ZFS, TrueNAS, Unraid and most hypervisors want. In IR mode the chip offers RAID 0, 1 and 10 only. There is no RAID 5 or 6, because parity RAID needs cache and a controller that can do the write penalty math. If you need parity, that is a MegaRAID job: the 9361-8i with 1GB cache or a 9460-class card. We compared cache sizes on the 9460 line in 9460-8i 2GB vs 4GB cache.
NVMe is not supported at all on the 9300. No U.2, no tri-mode, no PCIe tunneling to a drive. SATA drives work, at SATA link speeds, one drive per lane. Behind a SAS expander, SATA drives use SATA tunneling, and a small number of drive models behave badly in that configuration, so test before you build a 24-bay SATA pool on expander ports.
Which One Fits Your Build
Match the card to the chassis, then to the drive type:
- Up to 8 bays, HDD or SATA SSD: 9300-8i. Two cables, one slot, nothing wasted.
- 12 to 16 bays of SAS or SATA hard drives: 9300-16i. The extra ports are real and the x8 link is not the bottleneck.
- 16 bays of SAS SSD or any NVMe: skip the 9300 and go tri-mode on PCIe 4.0, such as the 9500-16i, or a smaller 9400-8i tri-mode HBA if 8 ports is enough.
- External disk shelf: 9300-8e, cabled with SFF-8644.
If you are buying used, run four checks before the card goes into a production build. First, confirm IT or IR firmware: sas3flash -list prints the mode and version, and a card sold as an HBA that answers IR needs reflashing. Second, assume cables are not included, because they usually are not, so budget four breakouts for a 16-port card. Third, look at the heatsink and plan airflow: these boards run warm and expect forced air from a server chassis, so a tower or desktop build needs a fan pointed at the card. Fourth, check the bracket height and test every connector, since a dead port group is easy to miss when only one backplane is wired.
Mixing drive types is fine within a tier, not across tiers. A pool of 10TB and 14TB HDDs works, as in our 10TB 7200RPM SAS 12Gb/s drives. Putting spinning drives and SSDs in the same RAID set wastes both.
The port count is the headline, the drive limit is the reality
- 16i means 16 internal SAS ports, 8i means 8 — but the drive limit also depends on the expander in the enclosure
- A backplane with an expander can present more drives than the controller’s port count suggests
- Jumper and cable configuration on the enclosure determines what is actually reachable
Matching the controller to the chassis backplane
- Internal HDX connectors on a server chassis and external Mini-SAS on a JBOD are wired differently
- Confirm the backplane type before assuming a port count maps directly to a drive count
- On a used card, check the connector type and the bracket before it arrives
Planning for growth and the practical limits
- Leave headroom for a hot-spare and for the expansion the next year will need
- Very large arrays need an expander and sometimes a second controller, which changes the design
- Rebuild time grows with the array, so a large drive count interacts with the RAID level choice
Related reading
- MegaRAID 9361-8i — the sibling SAS controller
- This comparison — self reference
- RAID vs HBA — HBA versus RAID framing
- RAID controllers — category hub
Frequently Asked Questions
How many drives can a 9300-16i attach?
16 internal SAS ports, and in a server chassis with an expander backplane that can present more drives than the port count implies. The practical maximum is set by the enclosure and its expander, not by the label on the card. Tell us the chassis model and we will confirm the reachable drive count for your backplane.
What is the difference between the 9300-16i and 9300-8i?
The port count — 16 internal ports against 8 — and consequently how many drives you can attach without an expander. Everything else is broadly similar: both are 12Gb/s SAS HBAs without hardware RAID, intended for pass-through into the operating system. Choose based on your backplane and drive count, not on anything else.
Does the 9300 series support NVMe?
No. The 9300 family is a SAS HBA generation and it does not attach NVMe drives. If your chassis has NVMe bays, you need the tri-mode generation — the 9500 or 9600 families. This is the single most common mismatch we see, so it is worth confirming the media before you order.
Is the 9300-8i enough for a typical server?
For a small or mid-size chassis, often yes. Eight drives with a hot spare covers a modest server comfortably. If you are planning to grow the array, the 16i gives you headroom without going to a tri-mode card, and the price difference is usually modest.
How do you verify a used 9300-series HBA?
We clean, re-flash and bench-test on our own test line, then confirm the part number, port count, connector type, port mapping and firmware level. We check that all ports enumerate and report the firmware level the unit ships with. Ask for photos of the actual card and the connector face before you commit.
Can I use a 9300-16i in a chassis with an external JBOD?
Yes, provided the external enclosure uses the connector the card provides — Mini-SAS on the 9300 family. A chassis with an internal HDX backplane needs a different card or an appropriate cable and expander. Tell us the enclosure model and we will confirm the connection.