RJ45 LEDs on PowerConnect 6224

I'm troubleshooting some user complaints of slow network response, and I'm looking at the link status lights for my PC RJ45 connections on the 6224.  All of the right LED's (above the RJ45 jacks) are solid green, meaning good connections (I think), but some of the left LEDs are blinking green and some are blinking amber.  On other switches I've used, I've understood a blinking amber light to mean that it's operating at 10/100 Mbps, rather than gigabit, speed.  Is this true of the 6224?  I've verified that all cables are cat-5e or cat-6, and the PC network card Link Speed is set to 1.0 GB full duplex, but there could be other errors in the line that's causing the link to downgrade.  The 6224 user manual isn't all that helpful in that it says blinking amber indicates "The powered device power conception exceeds the predefined power allotment"  

Thanks!