Online jewelry retailers were among the fastest-loading desktop and mobile websites this Valentine’s Day season.

Blue Nile Inc. (No. 96 in the Internet Retailer 2017 Top 500), Zales.com and Tiffany & Co. (No. 143) had the fastest-loading desktop sites, all loading in less than 2.4 seconds on average between Feb. 5-15, with Blue Nile leading at 1.4 seconds, according to digital performance analytics company Catchpoint Systems Inc.

Catchpoint monitored the web performance of 12 Valentine’s Day-focused retailers from Feb. 5-15. Catchpoint monitors each website’s home page with measurements taken from Catchpoint’s in-country or in-region monitoring nodes, at intervals of five minutes. Backbone monitoring nodes are the locations of Catchpoint’s devices that are near data centers operated by the main internet service providers that provide service to a city. The nodes simulate end-user contact with each website. Catchpoint monitors webpage load time, availability, hosts and items.

Some retailer sites, however, slowed down as Valentine’s Day approached, including flower retailers FTD.com (No. 128) and 1800Flowers.com (No. 59) and jewelry retailer JTV.com (No. 226).

“On the whole, the sites maintained good performance with a slight spike in load time over the weekend before Valentine’s Day,” a Catchpoint spokesman says. The weekend dates were Feb. 10-11.

The slowdowns were likely because of increased traffic, Catchpoint says. “All the websites maintained the same page size, hosts and items on the page, so the performance degradation could have been a result of increased traffic,” a Catchpoint spokesman says.

This correlates with traffic data from web measurement firm SimilarWeb. According to SimilarWeb, these retailers had increasing traffic throughout the month, and FTD.com and JTV.com both had spikes in traffic on Feb. 11.

While these websites did load slower in peak traffic times, overall, their average speeds both on desktop and mobile were less than five seconds. For example, 1800Flowers.com’s desktop site still loaded on average in 2.96 seconds, JTV.com’s desktop home page in 3.60 seconds and FTD.com in 4.06 seconds, according to Catchpoint.

For mobile websites, BlueNile.com, Zales.com and Tiffany.com again topped the list for fastest-loading sites.

Interestingly, the mobile sites for these Valentine’s Day-focused retailers loaded in comparable times to their desktop counterparts. For example, Kay Jewelers loaded in 3.98 seconds on desktops, which is the same as how fast it loaded on mobile.

Mehdi Daoudi, CEO at Catchpoint, says that desktop and mobile site speed similarities are on par with trends for top retail websites during the Cyber 5 peak holiday shopping weekend of Thanksgiving through Cyber Monday.

“We believe this is a result of the fact that more shopping, actual conversions, are occurring on mobile devices, and retailers know mobile site performance must be every bit as fast as the desktop experience,” Daoudi says. “They’re taking steps to ensure this, namely, keeping mobile content as slim and lightweight as possible during peak traffic periods.”

Catchpoint also notes that the mobile measurements are taken on a broadband connection and are a baseline test of mobile speed. The speeds are not impacted by 3G or 4G connections, and that mobile consumers likely will have slower loading mobile site times because of the constraints of their mobile network, Catchpoint says.

James Risley contributed to this article.