I'm not quite sure to whom That Is Slow! refers. Additionally booting a guest OS in an already running host is probably not a good comparison.
I suggest comparing boot times we use a benchmark to 'handicap' stastics ... I found a benchmark utility in Software Boutique that's gui driven and provides an extremely comprehensive output.
Certainly the entire report will be TMI for posting, but type cpu and 1 benchmark would provide others a comparison. Here's the type of output hardinfo produces:
Processor4x Intel(R) Core(TM) i3 CPU M 330 @ 2.13GHz
Memory7838MB (1289MB used)
Operating SystemUbuntu 16.04 LTS
User Namepfeiffep (Pete)
Date/TimeSat 30 Apr 2016 02:42:50 PM EDT
This Machine1066 MHz5.699
Intel(R) Celeron(R) M processor 1.50GHz(null)40.8816714
PowerPC 740/750 (280.00MHz)(null)161.312647
The Operating System identifies OS = Ubuntu, in my case really UM 16.04LTS