SG300-10 and 28 switches very slow over trunk

[pitbullstudio]

I have several SG300-10 and SG300-28 port switches in my network and I get very slow transfer speeds if I configure trunking on them.

We have 1 x Catalyst 3750G in our data center with a fiber trunk to 2 x HP 1810-48G switches that the office workstations are patched into. When devices are just connected to the HP switches transfer rates are very fast with no issues, however if I configure a trunk from the HP switches to any SG300-10/28 switch then the speeds are very slow (for the devices connected to the SG300's). If all the ports on the SG300's are in the same VLAN with no trunk (i.e. dumb switch) then the speeds are great which leads me to believe it's the trunk port causing the problem.

All the SG300's have been upgraded to the latest FW, and i've tried downgrading them too with no luck. I've tried tuning off flow control, and things like CDP and changing the port all of which have failed. 

Has anyone else seen this?

Regards

Rich

[pitbullstudio]

Just in case someone else see's this issue, I fixed it by configuring aggregated trunks between the HP and SG300 switches. No idea why the single port trunk was so slow, but this is working fine now so I'm not that bothered. The only real issue this has caused is the LACP connections take up more ports.