Any benchmark would do. But since very few db apps are cpu constrained, I would not bother too much and look at other aspects such as power consumption.
I agree with gmouse.
Choosing between AMD or Intel is not so important.
More important in this case then is things like:
1.
One can have dual quad core cpus and the other not.
Important if you know that your application issues alot of cpu intensive queries.
One has a CD/DVD reader and the other doesn’t.
Installation issues?
one has two ethernet ports and the only one
Possible separate network for backups etc?
One can host more hdd drives than the other.
Really large storage needs?
Or if any of the above is not important just go with the cheapest one. )