Where are Cache settings stored?

Question

I assumed the settings from the function system_performance_settings were stored in variables, but couldn't figure out which.

Answer 1

If you trace the code from the system_performance_settings, you'll see that is uses system_settings_form for form generation, which uses system_settings_form_submit form submit handling, which in turn does

foreach ($form_state['values'] as $key => $value) {
  if (is_array($value) && isset($form_state['values']['array_filter'])) {
     $value = array_keys(array_filter($value));
  }
  variable_set($key, $value);
}

So to find any individual variable name, your best bet is to

drupal_set_message($key);

in that function.

Answer 2

cache: 0
cache_lifetime: 0
page_cache_maximum_age: 0
block_cache: 0
page_compression: 0
preprocess_css: 0
preprocess_js: 0

Those were the results of @Letharion answer, disabling everything in the form.