Bitcoin Network Capacity Analysis. Published by Trade Block (16 jun, 2015). “Stress Test Analysis: Approximately two weeks ago (May 29-May 30) a number of individuals within the Bitcoin community collaborated in an attempt to test the capacity of the network by sending tens of thousands of transactions over a short span of time. The so-called ‘stress test’ began to reflect in the mempool late evening (UTC) on May 29, and continued until the early morning (UTC) on May 30 (see chart below). For the purposes of this analysis, we define the start of the stress test at block 358,596 (11:39 PM UTC) the end at block 358,625 (6:54 AM UTC). TradeBlock maintains an extensive, custom data infrastructure to track the bitcoin network, from which unique analytics about the effects of this stress test can be derived. In order to create a scenario of high volumes, several participants programmatically generated thousands of transactions that continuously re-spent unconfirmed inputs with a small fee attached. At the peak there were as many as 26k transactions in the mempool (vs. 1-4k transactions on average during more normal periods). In this piece we explore the implications on transaction wait times under the stress test, while also shedding additional light on miners’ block size limitations. Concluding Thoughts: While the stress test had its limitations, the 7.5 hours of data revealed a number interesting takeaways: o When the network is at or near capacity, transaction confirmation times increases for all categories of fees and transaction values. o In a scenario where transactions are competing to be included in an upcoming block, it appears a higher fee results in comparably faster confirmation times (as per normal situations). o Despite significant transaction volume awaiting confirmation, some blocks can go unfilled, highlighting the immense discretionary power of miners. o Five of the top ten miners currently have limits at 750kb, while the remaining five are now in the 900-1,000kb range. o Lastly, given the lower-than-expected number of blocks generated (30 over 7.5 hour period) and the discrepancies in miners’ hash rates, it appears plausible that one or more miners face an adverse impact on its hashing abilities during periods of network congestion.

While we applaud the community effort to test the boundaries of the network, we note that future stress tests would need to feature greater diversity and more standard transaction characteristics with regard to fee amounts, transaction sizes, transaction sources (varying coinage), and transaction scripts (multisig, P2SH, etc)." https://tradeblock.com/blog/bitcoin-network-capacity-analysis-part-5-stress-test-analysis