First of all we are comparing two products, one is desktop based while the other one is server class. Since you are going for Virtualization, servers are meant and designed specifically to cater for such needs so in this case I would recommend server based product such as Xeon CPU. Moreover all the Xeon CPUs mentioned here are quad-core and support DBS and Intel® I/OAT that improve network application responsiveness with more efficient data movement and reduced system overhead.
Furthermore as you mentioned, Q9650 is also a quad-core CPU based on 45nm technology with 1333MHz FSB while the Xeon CPUs have the same properties however the blocking agent is motherboard as you indicated that limits FSB since all the CPUs here support 1333MHz while boards specified do not allow anything beyond 667 or 800MHz but if you are more exact, I see that motherboards for E54xx support FBDIMMs (better performance, more reliability & density of memory systems) and ECC (more stable solution and minimal blue screens) memory that is bound to give you better performance and reliability than desktop boards that do not have support for ECC or FBDIMM.
Now if you are wondering that why the boards that support Xeon CPUs with higher FSB do not have a complaint FSB, that is because of the tick-tock model Intel follows which is, release CPU in one quarter and then the supporting chipset in the next. The motherboards that you find for E54xx in the market support 667MHz FSB because they are the older generation of motherboards supporting older gen of CPUs however they are forward compatible so they do support the newer Xeons. But if you check in the market, you might be able to look up a few boards with support for 1333MHz otherwise I would strongly suggest that you go for Xeon than Q9650 due to the reasons I stated above. Besides, the only significant difference in FSB performance you get in Q9650 over Xeons is 133MHz however what you would be losing on Q9650 in terms of ECC and FBDIMM would mean a lot more.
To answer your two questions though, I would go for:
- VSA with 8GB (considering your budget limitations)
Hope this helps you choose the system of your choice however at the end of the day, the choice is yours. Best of luck!
I would like to assume that you are already aware of the advantage of ECC and FBDIMM however in case you do not, here you go:
ECC but vs Non-ECC: http://www.tomshardware.com/forum/206747-30-memory-memory
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