In case you needed another reason to uninstall Adobe Flash, we've got one: It can drag down your PC by as much as 80 percent. Yes, 80 percent. So not only is Adobe Flash incredibly unsafe, it's a memory hog. And we've got the numbers to prove it.
As part of an upcoming roundup of the major browsers, we tested their abilities to handle Flash. Two browsers, Mozilla Firefox and Opera, do not include Flash, although you can download a plugin from Adobe to enable it. A third, Microsoft's new Edge browser, enables Flash by default, although you can manually turn it off. Both Internet Explorer 11 and Google's Chrome also include Flash, which you can disable or adjust within the Settings menu.
Testing in the real world
Let's start from the totally naive premise that Flash does not represent a security risk (because it clearly does). Vulnerabilities occur in the background, surreptitiously lifting your data, installing rootkits, and the like. But they don't impact your day-to-day browsing, right? Maybe not. But as our tests show, simply using a browser with Flash installed can have major consequences on performance.
As we did in our Windows 10 review, we used a testbed of 30 live sites, ranging from Amazon to The New York Times to iMore to PCMag.com. Most of the sites have embedded ads and trackers, which the sites use to track you, create a profile, and sell you stuff. Because the sites are live, there's always a possibility that ads and content can change from one visit to the next, but we did our live testing over the course of a single day to minimize this.
We tested Chrome 44, Windows 10's Edge 12, Firefox 39, Internet Explorer 11, and Opera 31--all the latest versions at press time. We ignored Apple's Safari browser--sorry, Apple. For Firefox and Opera, we ran our tests without Flash installed, then downloaded the plugin from Adobe's site. With Edge, we toggled Flash on and off, using its built-in control. We used a Lenovo Yoga 12 notebook with a 2.6GHz Intel Core i7-5600U inside, running a 64-bit copy of Windows 10 Pro on 8GB of memory.
Measuring the impact on your PC's CPU and RAM is somewhat subjective. Loading a page can take as little as a few seconds, for a text-heavy page with few embedded elements. Pages with embedded video, pre-roll advertising, and the like, can take over a minute. We tried to split the difference.
From our list of links, we cut and pasted each link into a new tab, weakly approximating how a user would add one tab, then another. But we did it quickly, to try and stress the browser by throwing a number of elements at it, all at once. After loading all 30 sites, we then waited 30 seconds for things to settle down, before opening Windows 10's Task Manager and recording the CPU load and memory consumption of both the apps as well as the background processes. If applicable, we added Flash's CPU and memory load as well. (We snapped a picture of the screen, then copied the values in by hand--a browser like Chrome, for example, has a ton of background processes, all dynamically changing by the second.)
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