Ember CLI takes 34 seconds to build on OSX SSD

Does anyone have any idea why it’s so slow and if there’s any way to make it faster?

The app/ directory contents 286 .js files.

First build: 34 seconds

Incremental build: 6 seconds

Computer configuration:

OS X Yosemite 10.10.3
2.7 GHz Intel Core i7 (2 cores)
8 Gb Ram
SSD disk
$ ember -v
version: 0.2.3
node: 0.12.1
npm: 2.7.6
$ ember server
version: 0.2.3
Livereload server on port 35729
Serving on http://localhost:4200/

Build successful - 34313ms.

Slowest Trees                                 | Total
----------------------------------------------+---------------------
Babel                                         | 10764ms
Concat: Vendor                                | 4180ms
JSHint app- QUnit                             | 3489ms
Babel                                         | 3281ms
ES6: App Tree                                 | 2446ms
StylusCompiler                                | 1779ms

Slowest Trees (cumulative)                    | Total (avg)
----------------------------------------------+---------------------
Babel (6)                                     | 15919ms (2653 ms)
Concat: Vendor (1)                            | 4180ms
JSHint app- QUnit (1)                         | 3489ms
ES6: App Tree (1)                             | 2446ms
StylusCompiler (1)                            | 1779ms

Incremental build:

Build successful - 6169ms.

Slowest Trees                                 | Total
----------------------------------------------+---------------------
StylusCompiler                                | 1142ms
ES6: App Tree                                 | 795ms
Funnel: App JS Files                          | 730ms
Concat: App                                   | 637ms
Concat: Vendor                                | 457ms
Babel                                         | 317ms

Slowest Trees (cumulative)                    | Total (avg)
----------------------------------------------+---------------------
StylusCompiler (1)                            | 1142ms
ES6: App Tree (1)                             | 795ms
Funnel: App JS Files (1)                      | 730ms
Concat: App (1)                               | 637ms
Concat: Vendor (1)                            | 457ms
Babel (6)                                     | 417ms (69 ms)