Does my PDF get uploaded anywhere?
No. The test runs entirely in your browser using PDF.js — the same open-source library Firefox uses to display PDFs. Your file never leaves your computer. We don't see it, we don't store it, and we don't transmit it. Confidential architectural drawings, NDA'd projects, and client documents are safe to test.
How accurate is the comparison?
Both times model the real 'double-click a PDF' experience — the kind you have when opening a file from Finder or Windows Explorer, where the timer starts before the app is loaded. The other-viewer time is computed as ~1.0 s cold-start overhead (app launch, library initialization, file dialog) plus 1.8× the measured pdf.js render time of your file. We use pdf.js because it's the open-source PDF library Firefox and many other tools use, and it's already loaded in your browser so we can time it precisely. The 1.8× multiplier accounts for the real-world performance gap between pdf.js and Adobe Acrobat, Apple Preview, Nitro PDF, and Foxit on heavy vector PDFs (those four are 1.4–2.1× slower than pdf.js in our testing — they prioritize feature breadth over raw vector rendering speed). The Ncored time scales linearly with file size from our internal benchmark on M4 Pro MacBook Pro (220 MB ArchiCAD → ~0.8 s) and includes Ncored's own cold start. Your hardware will vary by ±30%.
Why is the speed difference so big on large files?
Ncored is built specifically for the heavy-vector-PDF case: 50–220 MB construction drawings with thousands of vector objects, layers, and embedded images. General-purpose viewers (Adobe Acrobat, Apple Preview, Nitro PDF, Foxit) are optimized for breadth (forms, signatures, prepress, document conversion) which trades off raw rendering speed on vector-dense files. The bigger and more vector-dense the file, the bigger Ncored's advantage.
Why is the difference small on small PDFs?
Small PDFs (under 10 MB) don't stress any modern PDF viewer. Adobe Acrobat, Apple Preview, Nitro PDF, Foxit, and Bluebeam Revu all open them in under a second. Ncored is also fast on them — but the gap is small because there's not much to optimize. Ncored's real advantage shows on heavy construction drawings (50 MB+), where general-purpose viewers slow down to 5–15 seconds and Ncored stays under 1 second.
What file types can I test?
Any PDF file — construction drawings exported from ArchiCAD, Revit, AutoCAD, Vectorworks, SketchUp Layout; contracts; scanned documents; image-heavy reports; multi-page sets. Maximum supported size depends on your browser's memory (typically 500 MB).
Where can I download Ncored?
Ncored is available for macOS (native Apple Silicon) and Windows. Free 14-day full-feature trial, no credit card required. Download from the main page.