If you're looking for sheer, brute force, there's not much you could do against this octo core monster from Dell.
The SC1430 would cost you a mere £629 excluding VAT and delivery (although you could bring the cost down by using Quidco) and packs a heck of a punch.
Dell defines it as "a general-purpose two-socket tower server that brings value - price/performance, expandability and deployment flexibility - to small and medium business.
The SC1430 is perfect for businesses with little or no IT staff, offering relevant technologies customized to address unique business needs.
System features are "right-sized" for file/print, dedicated workgroup, email messaging and small web server applications in a small form-factor."
Although you don't get an OS, you still get two Quad Core Intel Xeon E5310 processor running at 1.6GHz with a total of 16MB cache, one year warranty, 512MB memory and a 80GB SATA disk. You don't get a mouse, floppy, keyboard or monitor.