Hi Flavien,
I would recommend you to try SAP Sizing to identify perfect H/W , Network , Storage etc. requirement details.
SAP.com -> SAP Service Marketplace -> Products -> Performance and Scalability .
direct link: http://service.sap.com/performance-scalability
There you would find three options
* Performance
* Sizing
* Benchmarks
Performance :
Performance tools are to identify the total application performance in a computer system, including throughput, individual response time, and availability.
Sizing :
Tools to determining the hardware requirements of an SAP solution such as network bandwidth, physical memory, CPU power, and I/O capacity. This can be used to fine tune your application requirements.!
There is a tool called Quick Sizer which is a Web-based tool (with some questionnaires) designed to make the sizing of SAP Business Suite easier. And its free of cost 
Benchmarks (Applciations):
This would give you more idea on different vendor devices tested to supported by SAP Business Products.
BR | Sreejith.