poweredge r720 not properly negotiating drive 6gbps capable speed

Hello.

PowerEdge R720 here

* all latest firmware updated and I MEAN ALL.

* all CERTIFIED DELL BRANDED drives

Twin Quad Core E5-2609 56GB RAM

6 x Dell branded 300GB SAS 15k: capable 6gbps, negotiated 6gbps

Seagate ST3300657SS revision ES66

2 x Dell branded Intel SSD DS S3500 480GB: capable 6gbps, negotiated 3gbps:

INTEL SSDSC2BB480G4T revision D201DL13

My problem is that the SSD are NOT negotiating at 6gbps.

I have updated the drives to the latest 6gbps firmware.

I have checked that force 3gbps transfer for SATA is not selected.

I removed the power and press the off button for 10 sec,

I swapped the drives trays, what else?

THANKS IN ADVANCE.

Randolph.