As it is running in JVM, this is more a question does Java supports multi-threading Not sure how much impact red5 server will have on the server itself (if any), but only for the xmpp and 500 users i would say any CPU will be more than enough. Back in the days i was running Openfire for 100-150 users on P2 300 MHz and 32MB RAM It was running (and still, but in the virtual machine) cmd only linux box, of course, so low resource usage from the OS itself. Though recently Openfire became more memory hungry (memory leaks or Java issues), but 8 GB looks enough.
Dual-Cores are often better than hyper-threading. Anyhow also a single-core 1 GHz core will be fine for Openfire with only a little bit traffic (normal usage). If it’s a new PC one should add also a powerful CPU as buying good hardware is usually cheaper than trying to optimize things later.
