HP Proliant 585 G2 from 2007. It has 4x6 AMD Opterons 8xxx with DDR2 etc. I guess it is no longer cost effective to run those 24/7, but they are still very pow

HP Proliant 585 G2 from 2007. It has 4x6 AMD Opterons 8xxx with DDR2 etc. I guess it is no longer cost effective to run those 24/7, but they are still very powerful. Old CPUs without power savings features are great for testing multi-threaded applications. Modern CPU might decide to switch-off some parts during test, rendering result inconclusive. This beasts power requirement looks scary, but with some care it runs in ordinary house. I use separate AC circuit usually used for air-conditioning. It is very loud (like hoover). I usually run it about 30 minutes a day. I work on concurrent Java stuff. Fork-join, CAS, low latency databases etc. I mostly use this machine to verify things I read somewhere. I found that about 60% of things I read about concurrency is wrong. For example messaging (actors) are not really that great compared to well designed threads with locks & CAS. Right now I want to replace memory allocator with global lock (linearly scales up to 6 cores) with CAS version, which should scale up to 16 cores.