Only if the CPU like ivb pentium/celeron/i3... could make a difference. Atom is weak, not only on architecture but also on design. Its performance result is just like an old, archaic AMD dual-core CPU, so the slightly 200mhz "improvement" won't make much a difference.
And, since it's a netbook, there is no way for OC. Even if u succeed, the additional heat may shorten the netbook's life. It's better to do some optimization if u feel it too slow for ya.