The 5-port SATA card that needs no drivers: JMB585 explained

Most motherboards run out of SATA ports long before they run out of drive bays. Six ports sounds like plenty until two go to your boot drive and a DVD burner nobody uses, and suddenly your NAS build is short by three. A SATA expansion card fixes that for less than a takeaway, and one chipset name, JMicron's JMB585, covers almost every card worth buying. Here's what it does, how it compares to the cheaper ASM1064, and how to pick between them.

What JMB585 actually is

JMB585 is a PCIe 3.0 x4 controller that adds five SATA 6Gbps ports. Critically, it presents itself to the operating system as a standard AHCI controller, the same interface your motherboard's built-in SATA ports already use. That's the "no drivers" part: Windows, Linux, TrueNAS, and Unraid all have AHCI support built in, so the card gets recognized and mounts drives the moment you plug it in. There's no vendor driver to hunt down, no separate installer, no risk of the card working today and breaking on the next OS update because a driver went unmaintained.

Why the bandwidth math actually works out

Five SATA 6Gbps ports have a theoretical combined ceiling of about 3 GB/s. A PCIe 3.0 x4 slot delivers roughly 3.94 GB/s. That headroom means JMB585 doesn't meaningfully bottleneck even if all five ports are saturated at once, which matters if you're running five SSDs rather than five spinning disks. This is the detail cheaper cards skip past.

ASM1064: the budget alternative, with a real trade-off

ASMedia's ASM1064 is the other chipset you'll see on SATA expansion cards, usually on four-port boards that cost less than JMB585 cards. It's the same driver-free AHCI story, so setup is identical. The difference is the slot: ASM1064 cards are typically PCIe 3.0 x1, which caps out around 985 MB/s. Split across four ports, that's oversubscribed the moment you're running anything faster than a mechanical hard disk. For spinning drives, which rarely exceed 250 MB/s each, you'll never hit that ceiling in practice. For SSDs, especially if you're running more than one or two on the card at once, the x1 slot becomes the bottleneck instead of the drives.

Which one to buy

If your build is spinning-disk storage, a media server or backup NAS full of hard drives, ASM1064's four ports and lower price are the sensible choice; you won't come close to saturating an x1 link with hard disks. If you're adding SSDs, running five drives instead of four, or you'd rather not think about the bandwidth math again, JMB585 is worth the extra cost. It's also the safer default if you're not sure yet what you'll fill the ports with, since five ports at full bandwidth covers more builds than four ports that might pinch.

Buying the card, not just the chipset

Check the listing names the controller before you buy. "5-port SATA expansion card" tells you nothing about which chipset is inside, and the cheapest unbranded cards sometimes use controllers with worse driver support or lower real-world reliability than JMB585 or ASM1064. If the listing doesn't say which chipset is on the board, that's worth treating as a red flag rather than an oversight.

Every SATA and NVMe card we stock names its controller (JMB585, ASM1064, RTL9210B, and the rest) right in the product title, so you always know what's actually on the board. See what we stock, or ask us which card fits your NAS build.