Slim

cat composer.json:

{
    "require": {
        "slim/slim": "2.*"
    }
}

cat htdocs/index.php:

<?php
require __DIR__ . '/../vendor/autoload.php';

$app = new \Slim\Slim();

$app->get('/hello/:name', function ($name) {
        echo "Hello, $name";
});

$app->run();

htdocs/.htaccess:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteRule ^(.*)$ /index.php [QSA,L]

$ du -sh slim 
584K    slim

$ ab -t 15 -c 10 http://bench-slim.dev.bogus.corp/hello/world
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking bench-slim.dev.bogus.corp (be patient)
Finished 21 requests


Server Software:        Apache/2.2.22
Server Hostname:        bench-slim.dev.bogus.corp
Server Port:            80

Document Path:          /hello/world
Document Length:        12 bytes

Concurrency Level:      10
Time taken for tests:   15.080 seconds
Complete requests:      21
Failed requests:        0
Write errors:           0
Total transferred:      5850 bytes
HTML transferred:       360 bytes
Requests per second:    1.39 [#/sec] (mean)
Time per request:       7180.881 [ms] (mean)
Time per request:       718.088 [ms] (mean, across all concurrent requests)
Transfer rate:          0.38 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    3   3.2      0       7
Processing:  5011 5551 1028.9   5039    7982
Waiting:       10  546 1029.2     29    2977
Total:       5011 5554 1030.9   5042    7988

Percentage of the requests served within a certain time (ms)
  50%   5036
  66%   5049
  75%   5049
  80%   5982
  90%   7107
  95%   7985
  98%   7988
  99%   7988
 100%   7988 (longest request)

Silex

cat composer.json:

{
    "minimum-stability": "dev"
    "require": {
        "silex/silex": "1.0.*"
    },
}

cat htdocs/index.php:

<?php
require_once __DIR__.'/../vendor/autoload.php';

$app = new Silex\Application();

$app->get('/hello/{name}', function($name) use($app) {
    return 'Hello '.$app->escape($name);
});

$app->run();

htdocs/.htaccess:

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f 
RewriteRule ^(.*)$ /index.php [QSA,L]

$ du -sh silex 
8,1M    silex

$ ab -t 15 -c 10 http://bench-silex.dev.bogus.corp/hello/world
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking bench-silex.dev.bogus.corp (be patient)
Finished 1773 requests


Server Software:        Apache/2.2.22
Server Hostname:        bench-silex.dev.bogus.corp
Server Port:            80

Document Path:          /hello/world
Document Length:        11 bytes

Concurrency Level:      10
Time taken for tests:   15.022 seconds
Complete requests:      1773
Failed requests:        0
Write errors:           0
Total transferred:      414463 bytes
HTML transferred:       19525 bytes
Requests per second:    118.02 [#/sec] (mean)
Time per request:       84.729 [ms] (mean)
Time per request:       8.473 [ms] (mean, across all concurrent requests)
Transfer rate:          26.94 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       1
Processing:    16   84  28.2     83     176
Waiting:       15   72  25.5     71     169
Total:         16   84  28.2     83     176

Percentage of the requests served within a certain time (ms)
  50%     83
  66%     96
  75%    104
  80%    109
  90%    121
  95%    131
  98%    141
  99%    149
 100%    176 (longest request)