2010 GS - power: 81 KW, 110 HP, 120 NM torque dry weight: 205 KG
2010 KTM990 adventure: 78 KW, 104.5 HP; 100Nm torque, dry weight: 209 KG
you do the math... maybe i'm missing something like speed of reving etc?
then again, i wouldn't argue too much with the bob-nob 
Those figures don't really help.
My bike has 98Hp, 72Kw and has a 215Kg dry weight, 265 wet. Comparing these figures my bike should be a slow pig.
I have not taken on a 990 but a 1200GS is more than welcome to come and give it a go.