Version: 54.0.2840.41
OS: Windows 10.1

Chrome has never launched fast on my machine, but it's gotten slower over the last few milestones.

From no chrome.exe processes running (and no other activity to speak of), launching Chrome takes 6 seconds. Launching a second profile, while a browser window from the first profile is running, also takes 6 seconds.

This is with all extensions disabled.

The bottleneck appears to be the CPU (the process uses 25-38% CPU on a 4-core machine for most of the 6-second startup time). There's a large number of I/O reads immediately on launching, but after that I/O stops until the browser window opens (to the NTP).

This occurs with both of my "real" profiles. I created a new, empty profile, and opening Chrome to that profile takes less than a second. Opening that profile after having opened a real profile is even faster. But opening a real profile after launching Chrome with the empty profile still takes ~6 seconds, opening the second real profile after that takes another 6 seconds, etc.

My Default profile directory in User Data is 1.4 GB (25k files).
My second real profile directory is 700 MB (12k files).
The empty profile directory is 33MB (763 files).

A low percentage of the data is cache (400MB for Default, 130MB for 2nd profile). Obliterating cache via Settings does not improve startup performance (if anything, it's slower now).

Stats:
CPU - i5-4670k at 3.40 GHz
RAM - 4x4GB (16GB total) (8-8-8-24 timings with XMP)
Disk - SSD over SATA 6Gb/s