[actionfromafar]

Those were most likely people with a motherboard with 4 CPU slots and with 4 CPUs plonked in there.

[phire]

I was going to suggest it could be dual-socket, with HyperThreading enabled, but looks like the survey is HyperThreading aware and only counts real cores.

So must be Quad Socket motherboards.

[Ekaros]

I don't think there was even any dual dual-core solutions for x86 available in 2004... So must have been some quad socket weirdness...

[Daneel_]

Unless I'm misremembering, the first dual-core CPU on the market was the Athlon 64 X2 in 2005, so I agree that these results are likely from servers running Steam.

Edit: a quick bit of google tells me both Intel and AMD released dual core CPUs in May 2005, with Intel beating AMD by a few weeks, so there you go.

[cheschire]

I’m guessing it was game server software running on rack mounted servers.