Five fun and useful uses for an extra PCI slot

Anytime I pick up a “new” desktop/server/workstation class system, I check out the available PCI slots to see what my I/O options will be. There’s usually some open space there, and sometimes (especially when I’m building a system from board+case) there will be available “slots” on the case with no corresponding PCI slot on the system board.

Based on a recent home office closet cleaning, I’ve been inspired to share my top five uses for a spare slot. 

1. Extra Network Interfaces

Left: Brocade BR-1020 dual port PCIe converged network adapter (CNA), currently starting at $30 on eBay. Brocade-tagged cables run $20+ each

Right: Intel Pro/1000 VT quad port PCIe Gigabit Ethernet card (left), from $20 on eBay, and Intel Gigabit ET quad port card, also from $20 on eBay.

This is probably the most obvious option. Most systems today have one or two Gigabit Ethernet ports, usually with Gigabit Base-T cabling. You can easily find PCI-X (backwards compatible with ordinary PCI) and PCIe controller cards with 1, 2, or even 4 Gigabit Ethernet ports.

With trunking or teaming, you can get into 10Gig throughput levels at lower cost, but remember that a trunk is limited to a single interface’s bandwidth per stream. So even with 100 single Gigabit ports trunked, you can’t send a single stream/file faster than a single port allows.

If you’re running a Windows desktop or server OS, or FreeBSD or Linux release, you’ll likely be able to find cards at $10/port or less. With VMware vSphere and Windows Server 2016, you’ll want to check the compatibility lists to make sure older cards are still supported; some older Intel or Realtek cards will require slipstreaming of a driver.

If you’re outgrowing Gigabit Ethernet, there are options for 10 Gigabit Ethernet as low as $15-20/port, although the most common cards are going to be around $100/port. Brocade BR-1020 is a good starting point, with support through vSphere 6.5, but you’ll need Brocade-ID’ed cables or SFP+ modules.

If you’d like to go retro, Infiniband cards are readily available for under $25/port. You can run point-to-point or pick up an older switch for a couple hundred (or less).

Heads-up: If you’re buying a server-class network card, make sure it’s PCI or PCIe (as appropriate for your system), and not a blade or chassis specific form factor.

2. Storage controllers


QLogic QLE2460 4Gb FC, Brocade BR-825 dual port 8Gb FC, Adaptec AAR-122xSA eSATA

From left: QLogic QLE2460 single port 4Gb FC (from $2, really!), Brocade BR-825 dual port 8Gb FC (from $150), and Adaptec AAR-122xSA external SATA2 RAID card (from $50)

A beefy rackmount storage server will often be outfitted with enough ports for everything you can fit in the system. If you’re trying to make the most of a Shuttle XPC or HPE Microserver, though, you want to check into a SATA or SAS controller. I’ve bought a box full of these over the past couple of years with various interfaces, cache options (or lack thereof), and internal/external port options, usually for well under $50 including cables.

For VMware or FreeNAS you’ll want a non-RAID card, or one that can be flashed to IT mode (Initiator Target) which gives you the same effect. Check the specs of your desired card, and the hardware compatibility list for your OS, to make sure you’ll get the most out of your storage.

If you’re just running a desktop or general platform, you can also look into eSATA/external SAS cards to expand your locally-attached storage. This may be especially useful if you don’t have USB 3.0 or better and don’t want to add a card.

Fibre Channel is also an option, with 4Gbit cards easily found for $10/port or so, and 8GBit cards in the sub-$100/port range. Note that if you buy a FC switch, you may need to look out for port and feature licensing. Point-to-point doesn’t have this concern, and most card makers have free firmware updates available online.

3. Drive bays

2017-04-25 15.27.01

Left: Kingwin KW-PCI2H25 two-drive frame, $16 on Amazon. Right, plastic bracket with interesting spelling, $6 from Central Computers in Silicon Valley. 

In my recent mini-HTPC storage server build, I found myself wanting more drive bays than I had in the case I’d chosen. Sure, I have velcro and double-stick tape, but that’s more grungy than even I want in my homebuild servers.

A number of companies have drive bays that fit a PCI slot but don’t use the slot itself. I have a Kingwin KW-PCI2H25 for example, which holds two 2.5″ drives in a single slot. You’d connect the drives individually to power and data connections, whether on the motherboard or a SATA/SAS controller card.

Note that some of these do have a stabilizer that goes into a PCIe slot, but they usually do not have an electrical connection.

4. Hybrid storage bays

Left: SilverStone dual M.2 card, $20 on Amazon. Right, SEDNA PCIe SSD card, from $38 on Amazon.

This option is sort of a cheat, in that it combines the storage controller and a drive bay. Usually these are PCIe cards with a dual port SATA controller, where one port is exposed for connecting a drive directly, and the other port has a power and data connector on the card itself, suitable for mounting a SSD or spinning disk.

Newer cards let you go beyond 2.5″ SSD, with one or more M.2 or NVMe card slots. Think of this as a DIY Fusion-io type card.

5. Supplemental cooling


StarTech expansion slot fan, $8 from Amazon.

As you read in the HTPC build piece, I had a cooling issue with a fully-loaded Xeon-D motherboard. I ended up installing two 80mm case fans, but I could also have used an expansion-slot fan card.

These cards don’t use an actual PCI slot on the motherboard; you connect them to a 4-pin Molex power plug off of your power supply, and put them in an appropriate place in your case to get the airflow where you want it. The hot air from your case gets vented out the back, so watch the cables.

These fans are available for $10-20 depending on the number of fans and controls. You’ll probably want one per case at most, unless you want to cool a specific card as well.

Bonus: A refreshing drive bay expansion option


ThermalTake XRay expansion bay option, from $50 on eBay.

You probably know that you can get drive bay expanders, which would let you use multiple hard drives, SSDs, or mSATA/NVMe flash drives in a standard hard drive bay (whether 5.25″ half-height or various 3.5″ variants, or even in a slimline optical drive bay module). And while this is a refreshing alternative, sometimes you just want a beer.

I picked up a used case recently at Weird Stuff, with lots of fans and cables and a power supply included. Nothing fancy per se, but what sold it for me was the presence of a ThermalTake XRay bay kit.

This kit takes a 5.25″ half height drive bay, and provides a lighter socket (with cigarette lighter) and a pop-out cupholder. Take those “4x cupholder” CD-ROM jokes to their logical extreme with one of these classic accessories from the 2006 time frame.

These may be a challenge to find, although I’ve seen them for $50-75 on eBay. And I wouldn’t recommend them for on-label usage, as smoking around a computer can be as bad as mounting a frosty beverage on a computer. But if you really want something to one-up your friends, this is probably a great option.

So where do we go from here?

Next time you’re pondering expansion of a desktop, workstation, or server, consider adding storage or networking, or sneaking some extra drives in. For a modest cost you can extend the life and performance of your system, and impress your friends or colleagues in the process.

What’s your most interesting expansion on a non-laptop system? Share in the comments.


Note: Links are either eBay Partner Network or Amazon Associates links, depending on where we feel you’ll get the best deals; purchases through these links will help us fund future gadget and gear acquisitions. Photos taken on a folding table are by Robert Novak (C)2017 of our own gear, others are vendor photos, in cases where we couldn’t find our items.

3 thoughts on “Five fun and useful uses for an extra PCI slot

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