It’s been exactly one month since the previous Obelisk update, and we have a ton of progress updates to share. Notably, we expect to ship Batch 1 units in the first or second week of July. As we will explain below, this is mostly due to the chip delivery schedule.

Additionally, at this time we do not have any updates on unit hashrate. We do have updates on prototype chip testing, and we explain below how this may potentially affect unit hashrate.

Chips

Last month, we explained that our ASICs had to go through a metal spin to fix three chip layers, and that the timeline was therefore pushed back by several weeks. We are happy to report that TSMC has shipped out all our final production chips, and they are currently being packaged!

You can read more about packaging here. This is the final step of chip production, and it is done by a separate packaging company. Essentially, the die is placed into a case that protects it from damage and provides electrical contacts. Once chips are packaged, they can be placed onto circuit boards.

We expect the first batches of chips to begin shipping to our chip team in 1-2 weeks. The team will then test each chip and sort them accordingly (more on that below). After a few days of testing and sorting, the team will start shipping trays of chips to our manufacturers. Therefore, we are about 2–3 weeks away from chips arriving at our manufacturers. It will take another 1–2 weeks for all chips to arrive.

From a performance standpoint, the clock speeds of our ASICs have high variance. When last month we reported minimum unit hashrate of 550 GH/s for the SC1, we were doing so based on a small sample size of early prototype chips. On SC1 chips, we were seeing clock speeds of around 300 MHz, which equals about 300 * 64 = 19.2 GH/s per chip. With 30 chips per unit, that was about 576 GH/s.

However, after a month of testing chips, our team has reported that they are seeing performance variances from 350 MHz to 600 MHz per chip. This means that, depending on the variance of our production chips, there is a good chance that we will be able to meet or exceed our unit hashrate targets. We will not know until we get our hands on production chips, and measure the statistical distribution of clock speeds. We are remaining cautiously optimistic.

Additionally, our chip team has informed us that the chips are expected to run faster at operating temperatures of 85–100 C. Our thermal simulations are showing that our chips should run at 85–90 C, so this may positively affect hashrate.

Boards

Each Obelisk hashing board has 15 chips. These chips run in a string (also known as in series), meaning that they share a common source of voltage and current. This practice helps pack more chips into a single board, and minimizes the number of components (and therefore cost) needed on a circuit board. But this presents an interesting set of challenges: unless chips are exactly equal, each chip needs to be optimally clocked, and changing the clock on one chip affects the entire string!

Halong explains it well in their recent blog post:

Due to the serial design of the PCB, chips are wired together like Christmas lights. It turns out our the chips have a much narrower tolerance to variance so we have to do more specialized sorting so that each board has similar “color”. The chips in the earlier miners were not so well sorted according to this precision and the miner manufacturing process was less mature.

Testing our hashing boards.

We will be sorting our chips accordingly, but our sorting methodology will improve over time as we better understand how to optimize strings of chips.

Additionally, there are many possible firmware optimizations to ensure that each chip is optimally clocked. In order to deliver units as soon as possible, we will likely be unable to make every possible optimization. This means that after delivery, we expect to release firmware updates that increase unit hashrate. This will be high priority for our firmware team.

Over the last couple weeks, we have been testing our control boards and hashing boards. Our electrical teams are making a few tweaks to each board, but everything is largely performing as expected.

Our control boards are about to be released for mass production, and our hashing boards are on target to be released by next Friday. It takes about 2 weeks to receive bare circuit boards. Once received, our manufactures will immediately begin building our production boards.

The bulk of our electrical engineering work is wrapping up next week, and most of our efforts will be focused on firmware over the next few weeks.