While the dc website may have an 'old school' look, I noticed that the average page size is not any smaller than your average website, if not bigger.
We average about 3 to 10 requests per second, depending on the time of the day.
Right now, with 10 requests/sec, load average is 0.26, 0.26, 0.2
... So yeah... fancy server
Beyond that it's just tweaking the apache Min/MaxSpareServers,ServerLimit,MaxClients and MaxRequestsPerChild values to match the capabilities of the server and reflected traffic. Though more tuning could be done there. We're just using the prefork MPM for now. But that probably will only affect anything under maximum load.
Other than that nothing special configuration wise, there's a lot more that could be done, and a lot more tweaking to do. But all that takes testing which we're not too keen on doing. ( prefer no downtime over 1ms faster loading page for now
So it's probably mostly due to the server being a beast.
(dual quad core (so 8 cpu cores total), 4GB ram)
Like mouser said, we rely 100% on continuous donations to keep this place running, so keep donating whenever you can if you want to keep seeing fast loading pages