Radeon HD 7660D Onboard dramatic drop in MH/s

[bigbeninlondon]

So for some reason my onboard Radeon HD 7660D just dropped from over 80 MH/s down to 20.  I can't figure out why and I can't get it to go back up.  I just reinstalled the drivers, nothing.  Temp would sit at 65-70 C with spikes to 75 Csometimes, now 30-35 C even when mining.  I'm using GUIMiner v2012-12-03; mobo is Gigabyte GA-F2A55M-HD2 with AMD A10-5800K APU, 650W PSU, 16GB RAM on Win7 64.

What can I check?  What would cause me to lose 75% of my hashing power?

[bigbeninlondon]

Anyone?  No thoughts?  I know 80 MH/s isn't much, but my whole configuration is putting out 1 GH/s so I'm not worried too much about the revenue.  I worry more that something happened to the mobo itself.  Dropping from 80 to 20 seems to point to something gone wrong.  I just don't know what else to check.

[Marrs]

This post seems to suggest the AMD APUs get recognized as two separate bits of hardware, so they require two separate workers in GUIMiner:

https://bitcointalk.org/index.php?topic=26145.msg1816794#msg1816794

[bigbeninlondon]

That's true; but the one that signifies the CPU portion only hashes around 1 MH/s so I don't use it.  The onboard card alone used to get me 80 MH/s, and then one day just dropped to 20 MH/s with no evidence as to why.

Edit to add:  I feel almost like something else is mining on my onboard and taking my hash power.  Is this possible?

[bigbeninlondon]

So I discovered the solution.  For some reason when a monitor is not plugged in to the card it gets significantly less hash power.  Weird.