Black Friday news kicked off early this weekend when the Best Buy website was hit with a massive outage, but it turns out that was only half the story. The top 50 ecommerce websites were slower overall this year compared to last, suggesting customers were frustrated even if they could get to their favorite shopping site.

Web performance monitoring company Catchpoint Systems looked at aggregate performance this weekend and compared it to the same timeframe in 2013. The results are notable: Desktop webpages were 19.85 percent slower, while mobile webpages were a whopping 57.21 percent slower.

More specifically, the firm made the following findings:

Median webpage response times for desktop websites for the entire group (aggregate) was 3.991 seconds, compared to 3.330 seconds in 2013.

Median webpage response times for mobile websites for the entire group (aggregate) was 2.954 seconds, compared to 1.879 seconds in 2013.

The data is for all of Black Friday (November 28, 2014) until 10:00 a.m. EST on Sunday, November 30. The comparison was made to the same time period in 2013: November 29 to the morning of December 1.

Catchpoint hints that the main reason for the slowdown was not simply because there were more users overloading the systems. Most webpages in the ecommerce group monitored by the firm were also bigger; there was simply more data on the page to download.

The five fastest desktop sites, according to Catchpoint, were H&M, Costco, Apple, Barnes & Noble, and Etsy. None of these five were present on the top five list for fastest mobile sites: Sears, WW Grainger, Office Depot, Ikea, and Saks Direct.

Best Buy actually went down more than once: twice on Friday, and also experienced issues on Thursday. Neiman Marcus was down for 2.5 hours on Saturday night, with poor availability leading up to the outage. Gamestop had poor availability all weekend, and J. Crew had slower-than-normal load times as well.

Catchpoint Systems conducts its performance tests on a customized list of 50 web and mobile sites identified as leading ecommerce retailers. The tests were run from 30 backbone nodes located in various U.S. cities, which the company says allows for noise and connection variables that occur in real-user environments to be factored out of these results.

We’ve asked for full list of the 50 ecommerce sites and will update this article when we hear back.

Update: The full list is now included below.