How can everyone run 5 or 6 erupters on a dlink and I can't?

I'm running Windows 7 (64 bit), cgminer 3.4.2, zadig, system fan pointing at all erupters.

I had 8 erupters running smoothly off of two Belkin 4 port hubs for several days (hw under 1%).  I have 12 more erupters so I thought I would grab a couple d-link 7 ports (same one everyone has been talking about).

My issue.... I can't seem to get more than 3 running on a dlink... no idea why.  Right now I have 14 running smoothly (8 on two Belkin hubs, 6 on two dlink hubs) for 28 minutes now.  As I write this, I'm plugging in a 4th erupter into one of the dlinks and... zombie.  Surprisingly, that only look less than 1 minute to happen.

Errors I see:

AMU1: Comms error (werr=-7 amt-0)
AMU4: Comms error (werr=-7 amt-0)
AMU 4 failure, disabling!

AMU5: TIMEOUT GetResults took 1001ms but was 100ms

My cgminer command line is:

cgminer-nogpu.exe -o http://stratum.bitcoin.cz:3333 -u xxx -p xxx

I don't have the icarus commands because the newer versions don't need it and just ignore it anyway.

Thoughts?