First, sorry for my poor english !
We plan to set up a virtualization infrastructure based on VMWare essentials plus (3 productions hosts). The goal is to run 30-40 VMs.
We are in trouble choosing between Intel 5650 (6x2.66Ghtz) and 5690 (6x3.4Ghtz).
Is the frequency's gain be really worth it (something like 5% of the project entire bill) ?
Usually is not important.
But if you plan to virtualize Terminal Server, XenApp Server or workload that could be CPU intensitive I suggest to look for more speed.
For other workloads a speed between 2 and 2.66 could be fine.
It is a difficult question to answer. Even though the cost is high it it's value will be spread across a number of years. Look at what is missing from your budget?. Are there other things that you could apply the cost difference and achieve a performance benefit. What would the cost difference as applied to faster disks in the SAN be worth?
For the disks I think that we'll have something that will fit our needs (EQL PS4000XV 15k SAS or NetApp 3210 15k SAS).
For the RAM I think 48GB (6*8GB) or 64GB(8*8GB) per server will be good (just don't know if going for 8*8 will be a good option since we'll go from 1333 to 1066 but I think that for virtualization, in a fight with memory quantity versus some speed quantity, quantity will win the fight (sorry for my english !!!).
We'll have some IT VMs (like DC, DNS, DHCP, some web apps, ...), some financial VMs (SQLServer but not really so intensively used) but we'll have some little satellite image based projects (large raster/vector) that may be CPU/disk intensive (development and support).
The fact is budget will be a hard fight for us but we need to design a realistic solution that will fit our needs.
Thanks for your answers with interesting responses and that made me think about it while answering !
I know well the Equallogic series, and a PS4000XV (with 16 disks) can run more than 50 VMs.
About the RAM this depends by the number of nodes and the VM usage.
If you use Windows Server 2008 R2 you may consider 2-3 GB for most of the VMs.
Your disk will be more important then the CPU by far.
Plus you have to consider what kind of jump you're making in the first place. If you're moving from x5650's in stand-alones right now you should probably go for the increase in clock. But if you're going from something like 5160's or older, the 5650's will be more than enough boost.