We are setting up a Windows 2008 Server to serve as NAT/VPN access server for our local network. Previous server we used for NAT/VPN was an Intel X3440 (single cpu) , during peak hours CPU usage was well over 80% !
Should we get a dual cpu or a single, faster, cpu ?
CPU Benchmark stats for i7 980x : 4
CPU Benchmark stats for Dual E5620 : 37
Although 980X is ranked better, maybe a dual cpu will perform better for this type of workload ?
Bearing in mind that 24Gb is the most RAM that i7 chip can address, and it's non-ECC and at a lower memory bandwidth, and that you're not able to scale to multiple i7s....
i7 - 3.33Ghz * 6 cores = 19.98 E5620s - 2.4 * 8 cores = 19.2
Whether your application is highly parallelized or not, the i7 still looks like it will narrowly edge out the E5620s for raw processing. However, there are better E56xx chips available and they'll exceed the performance of the i7, especially in 2-chip setups. You also need to pay attention to the memory bandwidth as all that extra processing power becomes useless if you transfer the data at suitable speeds.
Outside of these issues, also bear in mind that the intel server chips are designed for continuous operation and stress tested more completely than the i7s which are desktop targeted and generally no as robust.
Go for the dual Xeons, not only will you have three times the memory bandwidth but twice the IO bandwidth, larger caches, better concurrent out-of-order pipeline management, additional RRAS features plus additional future expansion capabilities by moving to >4-core CPUs.
