Rapid Spanning Tree failover more than 5 s on 2600 series

[Yannick_6]

After setuping RSTP on 2 2650 switches, the convergence time after a network failure is about 6 seconds. That seems really too long for such a simple configuration. Here it is:

- 2 2650 switches connected together on port 49 and 50 by cat5e cables.
- original config except:
- IP address
- spanning tree enable (RSTP)
- edge-port: no for port 49 & 50 of 2 switches
- priority of 4 for both port 49

That's it...I have not changed anything else from the orginal config. When I plug one PC on each switch, ping from one the other, disconnect the cable on port 49, it takes 6 seconds for my ping before getting a reply !

Any idea or similar issue ?
Thank you,
Yannick

P.S: they both have the latest firmware (H.08.54)