Here it is !!! This is the document I was looking for !!! [URL]  Notice that for 50 micron there's OM2 and OM3 specs. 62.5 is always OM1.  62.5 micron OM1 [NAME] can transfer data over 21 meters 50 micron OM2 [NAME] can transfer data over 50 meters 50 micron OM3 [NAME] can transfer data over 150 meters  21 Meters seem enough, but suppose you leave your storage array rack to reach a server in another rack in another room or simply 3 rows further in your data center ? 21 Meters is easily reached. I used to work in data centrers we had rows consisting of 10 racks per row and then 10 rows full of those. 21 Meters... We standardised on OM3.  You don't want to mix 62.5 OM1, 50 OM2 and 50 OM3. And if you also have long distance connections there's also 9 micron.... Keep the different sorts of cables as low as possible to avoid confusion.
Hoping someone can confirm this for me. I am failry new to SANs, however I understand the benefits and limitations of the different FC cable types. We have engaged a consultant to configure our new array. The entire SAN fabric is running at 8Gb, however the array bus speed runs at 4Gb (Clariion CX4-120). Our consultant has used 62.5um cables for all connections, however I was under the impression that 50um cables would usually be used for this type of connectivity. The longest cable run is 5m between host, switch and array.  What I would like to know is if there is any performance loss using older style 62.5um cables for fast 8Gb connectivity. Or is the cable run so short that the core size has no impact?
62.5 or 50 Multimode cable for 8gb SFP?