OWC Mercury Helios 3S Thunderbolt 3 PCIe Expansion Solution

Needed to find a new solution to add 1394a over Thuderbolt 3+, now that the latest firmware from Intel dropped legacy Thunderbolt 2 support. That meant I can no longer use the Thunderbolt 3 to 2 and Thunderbolt 2 to 1394b adapters from Apple on my Asus Maximus Z790 Hero. I also did not want to take up a PCIe slot on the motherboard. The Helios 3S allowed me to use my 1394 PCIe card via the Thunderbolt 4 port on my motherboard. So far it has worked flawlessly. Quality of the enclosure is top notch, and shipping was incredibly fast. Great product. I'm now able to use PowerSDR with my Flex 5000A (ham radio).

OWC specifies that this will work with PCIex Firewire cards BUT, Does not mention that if your planning on using this with ANY 1394 Firewire Card that if running your running a 12th Gen Intel Based CPU or Higher that Wonderful Intel Killed the 1394b PCIex Support altogether which was one of the reasons I had got this, NOW, it's a $250 Paper weight that only so an so works for certain PCIex card, Definitely not graphics cards if thats what your thinking about using this for. Originally, I had got this to use with a PCIex 1394 Firewire Card to use with my 13th Gen Intel I7 Lenovo Computer, Now I can't even do that which SUX!!!!

Works perfectly for adding a FireWire card which connects to my UA FireWire satellite.

Using this to house a UAD Octo card. works perfectly. Highly reccomended.

This sucker is handy as heck. One of the issues with the Intel NUC 12 Pro is that it's very sensitive to Thunderbolt peripherals. When running ESXi on a NUC 12 it's every more sensitive to issues with the Thunderbolt bus. I've been using this enclosure to add an external 10G network card to the NUC, and to daisy chain external storage that ESXi 8.02 will see. Works without issues on VMware HQL supported devices. It's well built and has a MASSIVE 12A power supply to be able to run anything you put in the chassis. My only complaint, per se, is that the PCIe bus is only 4x electrically, and 16x physically (which means that no 8x or 16x card will be running at x8 or x16 speeds.

Great product, does exactly what it says.

I’ve had this enclosure for almost exactly two years at this point (purchased April 29th, 2021). Took a bunch of pictures when I first got it but never got around to posting a review. So consider this a two years update. I’m using it with a Mellanox ConnectX3 10Gb Ethernet card. This is to free up the 2nd PCIe x16 slot on my motherboard, so my GPU can have full access to 16 PCIe lanes.This enclosure has performed flawless for the past two years. My iPerf numbers are exactly the same as when the NIC was mounted directly on the motherboard. It’s also completely silent even with the fan running. One unexpected thing is that the fan runs all of the time, even when my computer is off. But this is likely due to my TB port still supplying power when my computer is turned off, thus is specific to my hardware configuration. In any case, the fan looks easily replaceable should the need arise in the future.