I ordered 4 SilenX computer fans from Microbarn: http://www.microbarn.com/ (2) 120mm and (2) 80mm. The web site says they all have FDB - Fluid Dynamic Bearings.
When the fans arrived, the 120mm fan packaging said FDB, but the 80mm fan packaging said "Hybrid" for the bearing type.
Hybrid is another term for ordinary sleeve bearings.
I ordered FDB fans specifically because I have to mount them in three different orientations: Horizontal Up, Horizontal Down, and Vertical. FDB bearings will work in any orientation (like ball bearings) and sleeve bearings will NOT.
I powered up all four fans for tests.
I applied for an RMA number for the 80mm fans within 24 hours of receiving them, They have never been installed. Here is what I said:
Problem Description: The fans do not have FDB. The web site says they do. They do not work in the orientation I need. That is why I ordered the model with FDB (Fluid Dynamic Bearings). Here is the fan I ordered: http://www.microbarn.com/details.aspx?rid=101546 The ones I received do NOT have FDB. I have not opened/used the fans. Please accept their return, or send me 80mm fans that DO have FDB. Thanks.
And here is their reply:
The SilenX 80mm IXP-54-14 fans do have Fluid Dynamic Bearings. Here is the link to the manufacturer specifications: http://www.silenx.com/ixtremaprofans.asp?sku=ixp-54-14 The packaging has a misprint of Hybrid for the Bearings; it also has a misprint of 24CFM on the front of the package. The correct CFM of 32 is listed on the back. If you wish to further confirm the FDB with the manufacturer, their contact information is listed at http://www.silenx.com/contactus.asp If you still wish to return the fans, please use the RMA number you have been assigned but be aware that you will be assessed a 20% restocking fee for returning the fans if they are in original packaging and good condition.
Well, if the fans all behaved the same, I would believe them. They don't. In spite of my mail above, I did in fact open the 80mm fans just to test them by holding them, not installing them, and there is no way the 80mm fans have FDB. I believe they are old stock (a previous model) which DID have "Hybrid" bearings and Microbarn is simply trying to bully me into accepting them. I have seen older advertisements on the web for SilenX fans that have Hybrid bearings. It's clear to me what's going on.
Microbarn sold me a product that is not what they represent on their site, and they want me to pay a restocking charge for returning it to them. My recommendation: Don't by SilenX 80mm fans from Microbarn.
Mon Jun 15 23:34:28 PDT 2009
Update. My PC sounded a little quiet, so I just checked the fans. One of the 120MM fans has frozen and the center hub is distorted. It's been in service less than a year. I cannot recommend Silenx fans.