A fast price feed is a stream of market quotes used as a timely reference for comparison. Its relative speed depends on the instrument, the provider and the network path to the receiving system. For example, one feed may deliver a price change earlier for a given instrument during a test, while another may lead at a different time. Compare matching quote events from the same machine and record the distribution of arrival differences.
How to compare two price feeds
Record both feeds on the same receiving machine and compare matching bid or ask changes for the same instrument. A local arrival timestamp shows when that machine saw a quote. A provider timestamp records an event on the provider’s side and may use a different clock or timestamp convention.
For example, if feed A leads on one update and feed B leads on the next, the first observation alone cannot establish a consistent lead. Track how often each feed leads and by how much over a sample. Note missing or unmatched quotes separately.
Related guide: How to Check Which Quote Feed Is Faster.