"220V AC Cooling Fan" size usually associated with fan noise power related, usually the greater the power, the faster the speed, then a negative impact on the performance out of it, and that is noise. Therefore, when we buy "220V AC Cooling Fan", be sure to audition cooling fan noise, if too large, it is best not to buy; certainly noisy cooling fan, not necessarily a fan quality problems, there may be no fan shaft lubrication, or "220V AC Cooling Fan" was not installed correctly, if that is the case, we'd be able to re-locate to the fan, or fan shaft to add some lubricant to ensure lubrication good results.