Foursixty vs Stamped NPS: Shopify Performance Comparison
Both apps score Grade B — Stamped NPS has the edge with 10 ms vs 17 ms desktop CPU execution.
Both apps provide social proof and FOMO notifications functionality for Shopify stores. This page presents StackConflict’s independent lab results for both — measured in a clean-room environment with no other apps installed.
Head-to-Head Metrics
| Metric | Foursixty | Stamped NPS | Faster |
|---|---|---|---|
| Overall Grade | B | B | Tie |
| JS Payload | 107.52 KB | 107.0 KB | Stamped NPS |
| CPU Desktop | 17 ms | 10 ms | Stamped NPS |
| CPU Mobile | 39 ms | 39 ms | Foursixty |
| Layout Shift | 0.0006 | 0.0 | Stamped NPS |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-30.
Stamped NPS — The Faster Option (Grade B)
Stamped NPS scores Grade B with a JS payload of 107.0 KB and 10 ms desktop CPU execution. Mobile CPU: 39 ms. It passes every StackConflict threshold for payload, CPU, and layout stability — making it safe to install on any storefront including mobile-first stores where Time-to-Interactive directly impacts conversion.
View full Stamped NPS speed report →
Foursixty — The Heavier Option (Grade B)
Foursixty scores Grade B with a JS payload of 107.52 KB and 17 ms desktop CPU execution. Mobile CPU: 39 ms. Performance is acceptable but worth monitoring, particularly on stores with high mobile traffic share.
View full Foursixty speed report →
When to Choose Foursixty
- You need its specific features and can monitor its mobile impact
- Your other apps are lightweight (Grade A) so there is headroom
- You are on desktop-skewed traffic where CPU cost matters less
When to Choose Stamped NPS
- You need its specific features and can monitor its mobile impact
- Your other apps are lightweight (Grade A) so there is headroom
- You are on desktop-skewed traffic where CPU cost matters less
Performance Verdict
Result: Comparable — Both apps score Grade B — Stamped NPS has the edge with 10 ms vs 17 ms desktop CPU execution.
About This Test
StackConflict measures each Shopify app in an isolated clean-room environment — a single development store, no other scripts, Playwright-controlled browser. V8 CPU cost is the ScriptDuration delta before and after injection. CLS is captured from the same browser session. Results represent the median of three independent runs with outliers removed.
Data from the StackConflict Lab. Last updated 2026-05-30.