Follett Corp. rocketed up 59 spots to No. 4 in the Internet Retailer desktop performance index for the month of March.

Over the past few weeks, Follett, a seller of education materials and university-branded apparel that is No. 70 in the Internet Retailer 2016 Top 500 Guide, cut its number of hosts, items and overall page size, plus made changes to redirects, images and scripts, according to data provided by digital performance analytics company Catchpoint Systems Inc., which with Internet Retailer produces two monthly site performance indexes, one for mobile sites and one for desktop sites. Follett’s changes decreased its desktop home page load time to 1.5 seconds on average between Feb. 27-March 12 compared with 3.87 seconds on average between Jan. 29-Feb.12.

Follett.com also moved to a new content delivery network to serve images, which has helped decrease load time, a Catchpoint spokesman says. A content delivery network is a network of servers that delivers web content to consumers based on their location, the origin of the webpage and the location of the server.

Electronics retailer Dell Inc. (No. 3 in the Top 500) also jumped into the top 10 with a speedy load time of 1.57 seconds. Dell moved up 14 spots to No. 5 from No. 19 the previous month. Catchpoint attributes this to a reduction in hosts, especially ones that significantly contributed to slowing down the page.

Personalized products and photo books retailer Shutterfly (No. 46) was one of the most improved retailers on the index this month, as it shed four seconds off of its load time month over month, moving it to No. 26 from No. 93. In general, Shutterfly is a more media-heavy site and tends to have more images than the other retailers in the index, causing it to have a fatter site, Catchpoint says. For example, Shutterfly has 122 images compared with Amazon.com Inc.’s 63, Groupon Inc.’s 38 and Staples Inc.’s 61.

For the two weeks of Feb. 27-March 12, the top 100 retailers’ average load time was 3.43 seconds compare with 3.61 seconds the previous month. The average page weight was 2.58 megabytes compared with 2.42 megabytes the previous month, and the average number of hosts was 48 compared with 50. The average number of items was 168 compared with 173 a month ago. The top 100 sites were, on average, 99.90% available for Feb. 27-March 12 compared with 99.75% Jan. 29-Feb.12.

Catchpoint Systems monitors each website’s home page with measurements taken from Catchpoint Systems’ in-country or in-region monitoring nodes, at intervals of five minutes for two weeks each month. 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.

They are defined as follows:

Web page load time: The time it takes for enough page elements to load for a consumer to begin interacting with a page, such as searching, tapping or scrolling. From a consumer point of view, the time it takes for the progress bar or spinning wheel to stop.

Availability: The percentage of time during the two-week test week that the site can be successfully reached by a consumer.

Host: Any domain that delivers data, content or services over the internet to the site.

Items or Requests: Webpage components, such as files or images that a page loads from internal and external hosts or domains. These can include PDFs, PNGs, JPEGs and GIFs.