Acorn M.2 FPGA Based GPU Accelerator – Is GPU Mining Stronger than Ever?

Some months ago we have reviewed a new software that increases the hashrate for mining Ethereum. We were all shocked by how a simple program could squeeze up to 30% more hashrate from some of our GPUs.

Now, a group of developers led by David aka GPUHoarder has announced a piece of hardware that is capable of making our GPUs hash up to 100% faster on certain algorithms.

Meet the Acorn

Initially developed as a hashrate booster in a private mining farm, the Acorn has been kept private until a couple weeks ago. Besides a brief mention here and there, little was known about it until the founder of Squirrels Research Labs has announced that they are planning on releasing this device to the public.

The Acorn is a small FPGA board with 100k+ or 200k+ LE (logic elements) and small amount of ram (512 Mb – 1 GB) that can perform certain operations many times faster than any GPU.

When the rig is mining, the Acorn is streaming high bandwidth hash state between GPUs and the FPGA over PCIe. This means that memory bandwidth or area heavy portions of the algorithm will be handled by the GPU, while other parts are delegated to the FPGA.

Obviously, the Acorn works better on less memory-intensive algorithms such as Keccak and makes the least difference when mining, say, Ethereum.

Acorn in a Nutshell (no pun intended… kinda)

As we know, the Acorn module is a compliment to GPUs. Apparently, it will work with a wide array of GPUs no matter the manufacturer. The amount of hashrate boost will depend on the GPU model, though we don’t have any exact numbers just yet. I have joined the waiting list and I really hope to be one of the first members of the community to test this device on a wide variety of GPUs.

The Acorn can also be used as a stand alone miner with certain algorithms. This might be really interesting because most non-memory intensive algorithms are power-hungry. With only 15W of power consumption, the Acorn might revolutionize the way we mine those power-hungry algos (I’m looking at you, keccak)

Connectivity and Requirements

One Acorn module can be connected to the M.2 port to boost the performance of several GPUs. Motherboards that feature two M.2 PCIe GEN 3.0 x4 ports can be used with two Acorns and two GPUs to achieve maximum performance.

If your motherboard does not have a M.2 x4 port, you will have to use a PCIe x4 to M.2 M-key host board. Those are widely available and usually cost less than 15 dollars. It is also possible to use Quad-M.2 PCIe host boards to achieve up to 240 M/H acceleration.

In order to work in the GPU hybrid mode, you will have to have a free 4x PCIe 2.0 or 3.0 per Acorn device. Standalone Acorns can work with 1x PCIe (or M.2 x1) slots.

Ideally, you will use two Acorns to accelerate two GPUs and lift the hashrate for 30-60 MH/s per Acorn. More GPUs will result in less lift amount per Acorn. For instance, 8x GPUs on 1x lanes will cause bandwidth issues, which will result in considerable decrease of performance for the Acorns.  This means that while risers are ok to use, they are the least optimal option.

What about software requirements? Just like FPGA boards by FPGAland/Mineority (as discussed in my previous post), the bitstream for the Acorn will be developed by the community in a closed and safe ecosystem. While those bitstreams are free to use, there might be a 4% dev fee.

Price and Availability

As for today, the expected preorder prices are really modest. Developers said that they will charge the following:

 (*) They have also listed the CLE-215 model, though there have been no mentions about its features or price.

In the long run, the Acorn has got almost no maintenance fee –its power consumption hovers around the 15W mark, which is crazy if you keep in mind that one device can potentially boost your mining hashrate for an additional 30mh/s.

According to the developers, the Acorn is aimed to help small home miners. In a bit, we will find out that the Acorn works the best on rigs with fewer GPUs, which makes it even more attractive for those of us who are using our gaming PCs for mining.

In order to be among the first ones to access this product, you have to join the waiting list. If you are interested, you have to go and complete the pre-order registration survey, after which you will be notified if you get elected.

According to the developer, Acorn prototypes already exist, though we have to wait a bit more to have the exact stats (especially hashrates). The developer said that preorder will be open once he will have the exact numbers. This way we, customers, know what we are paying for. Expect to wait at least till early to mid July.

There have been delays in the testing of the product, mostly because GPUHoarder and his team are also working on the FPGA boards. That being said, the man claims that the delay affected the information, not the production of the Acorn. He promised to have the information soon, in maybe 2 or 3 weeks.

So far, we have two photos of the prototypes – in the first photo, the Acorn is next to the PCIe x16 slot to the right. You can see the little cooling fan on top of the board. The second picture is of two prototype Acorn boards on a M2 x16 riser card showing that the spacing is enough to fit 4 Acorns, if needed.

Acorn M.2 FPGA Based GPU Accelerator

Acorn M.2 FPGA Based GPU Accelerator 2

Read the announcement thread here: https://bitcointalk.org/index.php?topic=4391318.0

In Conclusion

Is the Acorn a step forward in the war against ASICs (or as some call it, ‘ASIC centralization’)? I don’t know, though if GPUHoarder delivers as promised, we might see GPU mining booming like never before. I do believe that FPGA is the future of mining, though it is great news for us that GPU mining might not be over just yet.

Make sure you subscribe to stay tuned with the latest updates on this topic. I am keeping a close eye on this. Also, I will be testing this board with the wide array of GPUs I own once they ship me one.