What the specs claim
Most commercial interactive panels advertise 20 or 40 touch points and a response time under 10 ms. In a meeting room, four people rarely touch the screen at once. The number is mostly a datasheet competition.
What actually affects the feel
- Writing latency — the delay between the pen tip moving and the ink appearing. Under 30 ms feels natural. Above 60 ms feels like writing with a rubber band.
- Palm rejection — whether resting your hand while writing creates stray marks.
- Jitter — whether a slow straight line comes out wobbly.
- Edge accuracy — whether the last 20 mm near the bezel still tracks correctly.
IR versus PCAP on feel
Infrared touch uses a frame of emitters around the edge and detects interruption. It is robust and cheap, and it can support very large sizes. PCAP uses a capacitive grid bonded to the glass. It tracks faster and feels closer to a phone, but large PCAP panels cost more and can be affected by thick gloves.
The test I run in a showroom
Open a whiteboard, draw a slow diagonal line across the full screen, then write a sentence in normal handwriting, then rest the palm on the surface while writing another. Repeat at the corners. Three minutes tells you more than the spec sheet.
Where the point count does matter
Collaborative tables and walls where six or eight people genuinely work at once. There, 20 points is a real requirement, and you should also check that the software can assign different pen colours per touch ID. Hardware that reports 20 points and software that merges them into one stroke is not 20-point collaboration.
A note on gloves and dust
In factory floors and clinics, IR often wins because it works through gloves and does not care about a dusty surface. PCAP with a glove setting exists, but the feel degrades. Match the technology to the environment, not to the brochure rank.