Bitcoin difficulty rises: check your rig's efficiency before the retarget

What is changing at the next retarget

CryptoSlate reported that network data pointed to another difficulty increase at the upcoming adjustment, with the exact size still open until the final blocks of the period arrive (CryptoSlate). The article focused on one practical question: how much room older, less efficient machines have between what they earn and what they spend on electricity.

The useful takeaway for a buyer is not the projection itself, which can shift from day to day. It is the habit of checking your own numbers before each retarget, so a change in difficulty never comes as a surprise.

Why difficulty moves your revenue

Bitcoin adjusts its mining difficulty every 2,016 blocks so that blocks keep arriving about every ten minutes on average. When more computing power joins the network, difficulty goes up. Each terahash you contribute then has a smaller chance of finding a block, so your expected share of rewards shrinks.

The effect on revenue is slightly smaller than the headline difficulty change. As CryptoSlate put it, revenue "scales inversely with difficulty", so a rise of a given percentage reduces revenue per terahash by a little less than that percentage, assuming price and fees stay where they are. In practice they rarely do, which is why it helps to look at live figures rather than a single snapshot.

Hashprice is the expected daily revenue from one unit of hashrate before any costs. It already combines difficulty, Bitcoin's price and transaction fees into one number, so it is the figure to compare against your electricity cost.

The efficiency check: J/TH times your tariff

Every ASIC has an efficiency rating in joules per terahash (J/TH). The lower the number, the less electricity it needs for the same output. Turning that rating into a daily power cost takes a few simple steps:

1. Find your machine's J/TH on its spec sheet, or divide its wall power in watts by its hashrate in TH/s.
2. Multiply J/TH by 24 and divide by 1,000. The result is the kWh one TH/s uses in a day.
3. Multiply by 1,000 to get kWh per PH/s per day, the unit most hashprice figures use.
4. Multiply that by your all-in electricity or hosting tariff per kWh. This is your daily power cost per PH/s.
5. Compare it with the live hashprice above. The gap between the two is your electricity cushion before other costs.

The energy side is pure physics and does not change with the market. A machine at 20 J/TH running one PH/s draws 20 kW, which is 480 kWh over a full day. The table shows the same figure for common efficiency levels.

A 30 J/TH machine uses twice the electricity of a 15 J/TH machine for the same hashrate. When difficulty rises, the cushion narrows for everyone, but it narrows from a smaller starting point for the less efficient unit. That is why efficiency is the first thing to check.

What this simple sum leaves out

The check above only covers electricity. A full picture also includes:

• Pool fees, which take a small share of rewards (see how mining pools work).
• Cooling and site loads, if they are billed separately from the machine's own draw.
• Repairs, spare parts and the time a machine spends offline.
• Any hosting terms that are not part of the per-kWh rate.

Two things can also work in your favour. A higher Bitcoin price or busier fee markets raise the value of each block, which can offset a difficulty rise. And difficulty can fall as well as rise if hashrate leaves the network. A retarget is one input among several, not the whole story.

Practical steps before the retarget

• Write down the J/TH of every machine you own or plan to buy, measured at the wall where possible.
• Confirm your full per-kWh tariff, including anything billed on top of the base rate.
• Run the efficiency check against today's hashprice, then again after the adjustment lands.
• When comparing new purchases, give efficiency as much weight as raw hashrate.
• Keep firmware and cooling in good order, since a dirty or hot machine drifts above its rated J/TH.

This article explains a method, not a forecast. Hashprice, difficulty and Bitcoin's price all change constantly, so always use current figures for your own decisions.

How hosting fits in

Your tariff is the one input in the check that you can choose. Segments hosts customer ASICs at its UAE centres, such as F21, with a clear per-kWh rate and an uptime target, and our team can help you run the efficiency check for the exact model you have in mind. For current rates and available space, see hosting or message us directly.