Inconsistencies in server performance and page delivery hamper website marketing efforts, it has been warned.
Research conducted by website testing service SciVisum found one per cent of all online transactions are impacted by poor performance, resulting in an estimated loss of £300 million in revenue each year.
But as many as one in ten of the "consumer online journeys" undertaken by the firm’s researchers resulted in "extreme inconsistencies in delivery speed".
The most likely time for loading speeds to be diminished coincides with the peak period of internet usage in the UK between 20:00 and 22:00 BST.
Online operators planning to use website marketing to boost sales in the run-up to Christmas are advised to ensure their server can provide content to visitors reliably.
"Companies wanting to maximise their online sales this Christmas need to check the performance of their sites now," urges SciVisum chief executive officer Deri Jones.
"Those that fail to do so might as well include a link to their competitors’ sites."
Jack Wallington, programmes manager for the Internet Advertising Bureau, recently urged small businesses to consult experts in search engine optimisation to ensure they are maximising the traffic reaching their websites.