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how many half-height server modules can poweredge vrtx support
The PowerEdge VRTX chassis has 4 half-height slots available for Ivy-Bridge based PowerEdge blade servers.
How many expansion cards can a PowerEdge VRTX system support
The PowerEdge VRTX system provides space for five PCIe Gen2 (2.0) expansion cards and 3 'full height' PCIe Gen2 (2.0) expansion cards.

Question: And power supplies
Self-contained rewrite: How many power supplies does the PowerEdge VRTX have