Think of bonded networks like a multi-lane highway. More cars can travel on the road with two lanes vs the road with one lane. BUT, the individual cars cannot go any faster. A bonded network connection will not double your speed. So, yeah, if you want to achieve higher speeds, you need different infrastructure, like 2.5gbe NICs and a 2.5gbe switch. Just adding a 2.5gbe switch will not make your 1gbe NICs any faster.