WordPress MU

My latest WPMU installation with 800+ blogs where i took these measures to reduce traffic:

--> Using lightweight themes with average loading time ~350ms
--> Plugins Multi-DB, Super Cache, Plugin Commander & a proprietary plugin for notice & event calender
--> Offload the static multimedia contents to Amazon S3
--> A proprietary widget to load RSS feed using AJAX, rather then embed the link.

This whole setup running behind load balancing server with a dedicated server for DB.
Average response time of this setup is nearly 650ms but if the with a average hit of ~18k/hour. But when the hit increase to ~30k/h the response time increase to ~850ms to ~1000ms

In my latest project I'm using WPMU for a university. There will be 1500+ blog as each department, faculty members & PhD student will have a blog.

So anybody have any suggestion to incase the performance?

There is a mu plugin to off load a lot of javascript to google

Thanks SteveAtty but they are already off loaded to Amazon S3.

I assume you've turned on compression and have something like eaccelerator installed?

yah sure Gzip compression for JS & CSS. eaccelerator 0.9.5.2

actually, you said you offloaded the static multimedia files to AS3. Steve suggested the *javascripts*.

what about phpspeedy?

i don't think there is any need of using phpspeedy. As I told before when Steve asked, I use mod_deflate for apache compression of static files like CSS & JS.

Then eaccelerator as the php compressor.

seems like you covered all bases but what do you mean by Average response time ? is it page generation time?

If so, try using the "wp tuner" plugin to analyze what components are taking longest and optimize further.

Also what is the total time from a client, Its not good being able to produce a page in .3 of a second if it then takes 2 to get it to the client.

I just ran Firebug against the BBC news website and it gives a total page time of 1.35 seconds.

Here is some stats:

Total objects:28 (346.1 KB)
External objects:24 (138 KB)
HTML:1 (10.2KB)
CSS:1 (12.5KB)
Scripts:2 (44.8KB)
Images:24 (278.5KB)

Using pingdom tool: loading time:6.6 seconds

Using our custom tool:

Run at: 2009-02-12 13:07:48 UST
Server Location: Singapure
Platform: RedHat Linux 5.0 Advance Platform
Apache httpd: 2.2.8
PHP: 5.2.2
MySQL: 5.0.45

|-------------------------------------
|Location | Response | Load (T1)
|-------------------------------------
|Bangalore | 0.38 | 6.8
|Shanghai | 0.56 | 6.99
|Sydney | 0.75 | 7.3
|Frankfurt | 0.63 | 7.16
|London | 0.78 | 7.2
|Orlando | 0.85 | 7.6
|Seattle | 0.99 | 7.5
|Atlanta | 1.02 | 7.8