depends on the weight of the rider + passenger, But it'll do it without issue either way.
I have a 2000 Shadow Ace 750 and used to ride with my ex gf all the time, no problems but on the highway it was a tad weak, but still didn't have problem passing. We would have been about 275lbs together.
My parents also had a 750 shadow, they weighted together about 350lbs and it still went on the highway, but had a harder time (of course) when passing.
General riding on back country roads, the 750 has no problem at all.
03 DRZ 400
05 VFR 800A
05 GSXR 1000
04 Honda 919
00 Honda Shadow ACE