One of our dedicated machines we use for hosting in London has exceeded the CPU usage, so I contacted the datacenter last week for a quote on an upgrade. We are hosting game servers, and most of these are single core applications.
Our current processor is the Q9550. They are offering us the Q9650 for 230$/mo or the i7-870 for 250$/mo. Since our customers are pushing the machine to nearly 100% CPU usage at peak times, which machine would we be better off going with? The Q9650 is a 3GHZ and the i7-870 is 2.93ghz. The Q9650 has a nice fat 12MB L2 Cache, and the i7 has a smaller 8MB L3 Cache.
I doubt either one is going to be much of a difference at all from the other, but would the i7-870 be worth it for hosting game servers?
On cpu benchmarks the overal performance of the i7 870 is 6073 points, the q 9650 has 4620 : http://www.cpubenchmark.net/high_end_cpus.html the memory bandwith is also larger on the i7 than on the Q. I think you are a lot more future proof with the i7, also when it comes to future games that might utilise more threading.
The difference isn't huge, but you might squeeze in 1 or 2 extra gameservers. So you should profit from using an i7 I think.