Pricing at Dell, it seems I can either get a single R430 or 3x R220's. The R220's would have 4C/8T processors, giving 24 threads. The R430 would have 2x 6C/12T processors giving again 24 threads.
For an CentOS 6 apache web server doing mostly dynamic content with Php (so some backend php calculation required), what would be the better choice given that the cost are the same.
Can do either bare metal install or virtualization (openstack). Obviously, the single R430 would take up less rack space, be easier to manage, and consume less power. But the assuming equal load, the Linux kernel on the R430 would likely have to handle 3x as many processes compared to 3x R220s.
By the way, this is not a duplicate question, as the answer requires an understanding of how the Linux kernel and scheduler scales with number of processes.