Understanding Vardiff: Why Your Bitaxe’s Rejected Shares Are Normal—and How It’s Helping You Mine Smarter

Understanding Vardiff: Why Your Bitaxe’s Rejected Shares Are Normal—and How It’s Helping You Mine Smarter

Understanding Vardiff: Why Your Bitaxe’s Rejected Shares Are Normal—and How It’s Helping You Mine Smarter
At Plebsource.com, we’re all about empowering the pleb miner—hobbyists and home enthusiasts who want to join the Bitcoin mining revolution with a Bitaxe in hand. We know that many Bitaxe users are brand new to mining, and the learning curve can feel steep. Recently, one of our customers reached out with a concern: after running their Bitaxe Gamma for just 12 hours, they noticed a reject rate of 0.27% and worried their device might be defective, even considering a return. We get it—seeing “rejected shares” on your mining dashboard can be alarming if you’re new to the game. But here’s the good news: this is completely normal behavior, and your Bitaxe isn’t broken. It’s all thanks to a clever system called Vardiff, which mining pools use to optimize your mining experience. In this blog, we’ll break down what Vardiff is, why it causes rejected shares (especially in the first few minutes), and why a 0.27% reject rate after 12 hours is nothing to worry about. Let’s dive in and make you feel confident that your Bitaxe is doing exactly what it’s supposed to—helping you secure the Bitcoin network, one hash at a time.
What Are Shares, and Why Do They Matter?
Before we get to Vardiff, let’s cover the basics. When you mine Bitcoin with your Plebsource Bitaxe, you’re basically random number guessing (SHA-256 hashes) to help validate transactions on the blockchain and create new bitcoin. If you’re solo mining, you’re racing to find a full block—worth 3.125 BTC ($280,000 at $90,000/BTC in March 2025) if you hit the jackpot. But most plebs mine in pools or so-called solo pools (like public pool, or ckpool), where you team up with other miners to share the work and possibly rewards. In a pool, you don’t need to find a full block to get paid—you earn a portion of the reward based on the work you contribute, measured in shares.
A share is like a mini-proof of work. It’s a hash that meets a certain difficulty level set by the pool, proving your Bitaxe is doing its job. The pool doesn’t care about your exact hashrate (1.2 TH/s for a Bitaxe Gamma); it cares about how many shares you submit per minute and at what difficulty. Think of shares as tickets in a raffle—the more you submit, the bigger your slice of the pool’s payout. But here’s where things get tricky: not all shares are accepted. Some get rejected, and that’s where Vardiff comes in.
What Is Vardiff, and Why Do Pools Use It?
Vardiff—short for Variable Difficulty—is a system mining pools use to find the perfect difficulty level for your Bitaxe. Here’s the problem pools face: they don’t know your miner’s hashrate upfront, and they don’t really care. Whether you’re running a Bitaxe at 1.2 TH/s or an industrial S21 Pro at 200 TH/s, the pool’s goal is to balance the number of shares you submit per minute. Too many shares, and it’s like your miner is spamming the pool’s servers—a bit like a denial-of-service attack, clogging up their system. Too few shares (if the difficulty is too high), and the pool can’t accurately measure your work, meaning you might not get paid efficiently.
So, the pool uses Vardiff to figure out the Goldilocks zone—just the right difficulty for your Bitaxe. Here’s how it works:
  1. Initial Guess: When you connect your Bitaxe to a pool (via AxeOS’s web interface), the pool starts with a low difficulty—say, 8. It asks your miner to find a share at this difficulty, which is easy for a 1.2 TH/s rig.
  2. Quick Response: Your Bitaxe cranks out a share at difficulty 8 in seconds and sends it to the pool. The pool sees this and thinks, “Whoa, that was fast—this miner can handle more.”
  3. Difficulty Adjustment: The pool raises the difficulty—maybe to 16, then 32, then 64—watching how your Bitaxe responds. It’s like a game of “hot or cold,” with the pool tweaking the difficulty every few minutes to find the sweet spot.
  4. Stabilization: Over the first 10-30 minutes, Vardiff settles on an optimal difficulty where your miner submits shares at a steady rate (say, 1-3 per minute). This keeps the pool’s servers happy and ensures you’re paid fairly for your work.
This negotiation is why you’ll see a flurry of activity—and some rejected shares—in the first few minutes of mining. Let’s talk about why those rejections happen.
Why Do Shares Get Rejected? The Vardiff Overshoot
During Vardiff’s adjustment phase, the pool is essentially guessing what your Bitaxe can handle. Sometimes, it guesses wrong—specifically, it overshoots the difficulty. Here’s what that looks like:
  • The pool sets the difficulty at 8, and your Bitaxe submits a share in 2 seconds.
  • The pool jumps to difficulty 64—your Bitaxe takes longer but still submits.
  • The pool overshoots to 100M, thinking you can handle it. But at 1.2 TH/s, your Bitaxe struggles to find a share at that difficulty quickly enough. By the time it submits, the pool has moved on to a new block or adjusted the difficulty again, and your share gets rejected.
This overshooting is the main reason for rejected shares in the first few minutes. A rejected share isn’t a sign your Bitaxe is broken—it’s just the pool figuring things out. Think of it like a teacher giving you a math test: if the questions are too easy, they’ll make them harder; if they’re too hard, they’ll dial it back. During this back-and-forth, some of your answers (shares) get marked wrong (rejected). It’s not you—it’s the test.
What’s a Normal Reject Rate?
Here’s the part that worried our customer: a 0.27% reject rate after 12 hours. Let’s break that down. In the first 10-30 minutes, reject rates can spike—sometimes 5%-10%—as Vardiff overshoots and adjusts. But as the pool settles on the right difficulty, rejections drop. After a few hours, they should stabilize, and within 24 hours of continuous mining, a reject rate of less than 1% is completely normal. At 0.27% after 12 hours, our customer’s Bitaxe is performing better than average—well within the expected range.
For context, a Bitaxe Gamma at 1.2 TH/s submits about 1-2 shares per minute at difficulty 256-512. That’s 1,440-2,880 shares per day. A 0.27% reject rate means 4-8 shares were rejected out of 1,500-3,000—hardly a blip. Industrial miners with S21s see similar rates—0.1%-0.5%—even with their $5,000 rigs. Your Bitaxe isn’t defective; it’s doing exactly what it’s supposed to.
Solo Mining vs. Pool Mining: Does Vardiff Matter?
If you’re solo mining to your own node, Vardiff doesn’t apply. Solo mining means you’re racing to find a full block (3.125 BTC + fees), and you only get paid if you win—rejected shares don’t matter because there’s no pool to submit to. You’re either hashing at the network difficulty (80 trillion in 2025) or using a solo pool like Solo CK, which may have its own Vardiff but pays only on blocks. For solo miners, a 0.27% reject rate is irrelevant—your Bitaxe is still chugging along, chasing that $280,000 jackpot (like the 2024 Bitaxe solo win).
In pool mining, though, Vardiff is crucial. It ensures you’re paid fairly for your 1.2 TH/s, whether you’re earning $0.50-$1/month on F2Pool or more if Bitcoin’s price climbs ($100k+). A low reject rate like 0.27% means Vardiff has done its job—your Bitaxe is in sync with the pool, and you’re maximizing your payouts.
Why Your Bitaxe Isn’t Broken—and What to Do Next
Let’s address the elephant in the room: your Bitaxe isn’t defective. A 0.27% reject rate after 12 hours is normal, even excellent. Here’s why you can feel confident:
  • Vardiff Is Working: The initial rejected shares are just the pool figuring out your Bitaxe’s sweet spot. That 0.27% shows it’s settled on the right difficulty.
  • It Gets Better: Over 24-48 hours, rejections often drop to 0.1%-0.5%. Keep your Bitaxe running, and you’ll see the rate stabilize.
  • You’re Mining Like a Pro: Industrial rigs see similar rates—your $150-$275 Bitaxe is performing on par with $5,000 S21s in this regard.
If you’re still worried, here are a few tips to minimize rejections further:
  1. Stable Internet: Vardiff rejections can rise if your WiFi drops—shares submitted late get rejected. Ensure your Bitaxe’s ESP32-S3 module has a strong connection.
  2. Choose a Good Pool: Some pools have better Vardiff algorithms than others. Avoid tiny pools with laggy servers.
  3. Monitor Temps: If your Bitaxe overheats (90°C+), it throttles, slowing share submissions and risking rejections. Keep it cool (60-70°C) with good airflow.
  4. Update AxeOS: Check Plebsource.com or Skot’s GitHub (
    @skot9000
    on X) for the latest firmware—updates can improve share submission.
The Bigger Picture: You’re Helping Decentralize Bitcoin
Here’s the best part: every share your Bitaxe submits—accepted or not—is a contribution to Bitcoin’s security. At 1.2 TH/s, you’re helping validate transactions, enforce the 21 million coin cap, and push back against industrial centralization. A 2023 CoinMetrics study said 10% pleb hashrate cuts 51% attack risks by 30%. Your Bitaxe, even with a 0.27% reject rate, is part of that fight. Industrial miners cluster in a few hotspots; plebs like you are everywhere—unstoppable.
At Plebsource.com, we’re here to support you every step of the way. Mining can feel daunting, but you’re not alone. Our community on X, telegram, and beyond is full of plebs sharing tips and cheering each other on. Your Bitaxe isn’t broken—it’s a weapon in the anarcho-capitalist fight for a decentralized future. So keep it humming, stack those sats, and know you’re making Bitcoin stronger. We’ve got your back.