The phrase "laggy performance" means that something (like a device, game, or application) is not running smoothly or quickly. It may be slow, have delays, or not respond well. Full definition
In the cabin, there are all the modern bells and whistles, including a touch - screen display with navigation that unfortunately suffers from laggy performance. (autofocus.ca)
Samsung has taken good 7 - inch tablet and made it even better: Light; improved but sometimes laggy performance; excellent 1024x600 display that works indoors and outdoors; expandable storage (up to an additional 32 GB SDHC); reasonably good cameras that record VGA or 720p HD video; updated Android OS that is actually designed for tablets; and enhanced TouchWiz. (androidthoughts.com)
The device had a great screen but problematic bugs caused laggy performance and low scores. (techcrunch.com)