wp-super-cache 0.9.9.9 object cache support

I have WP 3.0.5, HyperDB, memcache and the wp-total-cache plugin installed without caching the database. I decided to install the latest version of wp-super-cache 0.9.9.9 which has an experimental object cache support to check if it was going to work on my environment.

Things seams to be caching well in memcache (hits and amount of data) but when I try to benchmark the performance of the website it shows me that there is something with it.

I am using Apache’s benchmark to get those numbers

# ab -c 10 -n 100 URL

Without any caching system: 29.00 Requests per second
W3-total-cache without database caching: 603.76 Requests per second
wp-super-cache without object cache (disk caching): 983.00 Requests per second
wp-super-cache with object cache: 26.55 Requests per second

I believe that there is something wrong in my configuration…

I have the following options selected in the plugin:

Caching:
X Cache hits to this website for quick access. (Recommended)
X Use PHP to serve cache files

Miscellaneous:
X Compress pages so they’re served more quickly to visitors. (Recommended)
X Cache rebuild. Serve a supercache file to anonymous users while a new file is being generated. (Recommended)

Advanced:
X Mobile device support.
X Use object cache to store cached files. (Experimental)

and I get this at the bottom of the page source:

<!– Dynamic page generated in 0.163 seconds. –>
<!– Cached page generated by WP-Super-Cache on 2011-04-18 17:03:37 –>
<!– Compression = gzip –>

Is there anything that has to be done in order to get the object cache support for wp-super-cache working??

Thanks!