- Xeon X3430
Its a Intel Nehalem generation processor. Hence It falls under EVC level 'L2' and EVC Base line 'intel® "Nehalem" Gen. (formerly Intel® Xeon® Core™ i7)'.
- Xeon E5504
This too an Intel Nehalem generation processor. Again a EVC level 'L2' and EVC Base line "intel® "Nehalem" Gen. (formerly Intel® Xeon® Core™ i7)" candidate.
- Xeon E5-2407
Its a Intel Sandy Bridge generation processor. It falls under EVC Level 'L4' and EVC Base line "Intel® "Sandy Bridge" Generation".
The higher level EVC baselines will support the processors from lower baselines. Pls refer the KB mentioned previous comment ie, KB http://kb.vmware.com/kb/1003212)
In general, if a processor can support EVC level XN, it can also support levels XN-1 to X0. For example, a processor that supports the Intel® "Sandy Bridge" Generation EVC Baseline has an EVC level of L4. Therefore, it can also support EVC levels L3, L2, L1, and L0. However, it cannot support EVC level L5, which corresponds to the Intel® "Ivy Bridge" Generation.
so the ideal EVC baseline for your cluster is "Intel® "Sandy Bridge" Generation".
Note: the following wiki will help you to find the archtecture (eg: sandy bridge, nehalem etc) of a intel processor.
http://en.wikipedia.org/wiki/List_of_Intel_Xeon_microprocessors
