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rspoon18 t1_j6ge9pw wrote

Reply to comment by jaa101 in ELI5: Why are contactless payment methods faster than inserting the chip? by jimmysofat6864

Au contraire, "communication speed" absolutely is an issue. IT is the payload size("amount of data") that is not an issue. Communication speed (data transmission Round Trip Time aka RTT) doesn't change based on payload size - it is a constant based on the laws of physics.

A RTT across the continental US will take minimally 70-80 ms (plus remote processing time, which is the actual time hog since database lookups are S-L-O-W compared to data transmission) whether you send a single 64-byte packet or thousands of 1500-byte packets (to be more precise the larger packets take slightly longer in parts of the network that are not packet switched, but the difference is on the order of a few milliseconds, unperceiveable by humans).

See what /u/saywherefore said above for the most likely explanation based on actual response times.

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cache_bag t1_j6h9xfx wrote

But it's the same card, confirmed by OP. I'd understand if it's say credit card EMV vs Apple Pay. But if it's same card, it should be undergoing the same process in talking you the bank. The only difference would then be isolated to the actual tech (or how the app coded the communication with the tech). So the argument made by top answer regarding validity of the card shouldn't be a factor.

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