9 Tools to View Large Files on Windows Without Lag

Featuredcrop 1350x675

If you’ve ever tried opening a very big file on Windows, you might have experienced your computer slowing to a crawl or even freezing completely. Many of the default programs on Windows (especially older versions) are not developed with performance in mind and struggle to process massive amounts of data.

To give you a hand with that, we’ve put together a list of highly optimized programs that have no problem letting you view very large text, image, Excel, and video files.

The Best Programs to Help You Handle Large Files

For the purposes of this tutorial, we used a laptop running a Windows 11 virtual machine with a 3.2 GHz CPU (4 cores), 8GB of RAM, and an SSD. We chose a moderately specced computer with only 8GB of RAM to test how these programs fared with less power. Please note that we can’t possibly conduct all of these tests on every possible hardware configuration. Results can vary wildly depending on computer hardware, operating system versions, other processes running at the time of testing, and the specific test files used.

1. Notepad++

To work with huge text files, the free and open source Notepad++ is by far the best editor. We tested this by creating a 750MB text file containing six million lines of text, then opened the file in various text editors and measured the results.

Large Files Notepad Plus Plus Text Dark

In our experience, Notepad++ could open our six-million-line text file in just three seconds and speedily perform operations like scrolling, editing, and saving the document. Additionally, as an editor that is primarily used by software developers to edit code, it has nice features, such as syntax highlighting, for editing source code files. Notepad++ also has powerful search features – for example, it can look for text across files using regular expressions.

Large Files Notepad Plus Plus Text Dark Find

A clear downside was the interface. It looked 20 years old and was not the most intuitive. For instance, Ctrl + T did not open a new tab as it would in most other programs (which use Ctrl + N). There also wasn’t a command palette, which many modern programs have, to easily discover and execute actions.

Yet, these minor downsides will be a small price to pay for anyone who frequently handles large files.

2. Sublime Text

Sublime Text is a popular code editor that is mostly free to use. When it came to speed, it took about 20 seconds to open our text file – making it as slow as the default Windows Notepad. At least Sublime Text displayed a nice loading bar instead of “Not Responding” while we waited.

Large Files Sublime Text Loading

While the initial load time was poor, this editor still managed to let us view and scroll through our text file smoothly. Editing and saving the file was also successful – the operation just took a second or two longer than it did with Notepad++.

Large Files Sublime Text Command Palette

Use Sublime Text for its overall feature set. It comes with far more capabilities and a more modern UI than Notepad++ and is available on platforms beyond Windows, so you’re good if you work with multiple operating systems.

3. nomacs

nomacs is one of the best free programs for viewing extremely high-resolution images. We confirmed this by downloading a JPG image with a resolution of 39,137 x 22,279 pixels and opening it with various programs.

Large Files Nomacs Zoomed In

nomacs successfully opened the image and displayed it in its full resolution after a moderate waiting time. We also zoomed and panned the image using nomacs without too much lag, zoomed deep into a small area, and quickly and clearly saw the tiniest of details.

Using the image-editing features did cause the program to become unresponsive, but this is to be expected for such a large file, and similar editing we attempted on the other programs caused further unresponsiveness. Unfortunately, nomacs seemed to have poor memory management – it had wild spikes in RAM usage and eventually consumed all of our computer’s 8GB of RAM.

4. Microsoft Photos

Interestingly enough, the free Microsoft Photos app on Windows 11 was able to handle our large image file about as well as nomacs.

Large Files Microsoft Photos Full

Opening the file was very fast, with almost no wait time, and we were also able to pan and zoom into the image very quickly. Microsoft Photos’s memory management was solid – the program’s RAM usage remained stable at 3GB.

However, when we zoomed in to a small area, the picture was initially very blurry. It took a while before our zoomed-in view cleared up. The initial opening was so fast, Microsoft Photos was first showing a lower quality version of the picture while still loading the full-resolution picture quietly in the background.

Large Files Microsoft Photos Zoomed

The big problem with Microsoft Photos is that it is only available on the Microsoft Store. This makes it unavailable on older versions of Windows – those of you still on XP will be out of luck!

Additionally, being a Microsoft Store app may be an issue for anyone who wants to avoid interacting with Microsoft services as much as possible. All in all, despite some flaws, Microsoft Photos is an excellent program for viewing large files.

5. Caesium

If you still have problems viewing large images, you can resize or compress the images themselves before viewing them. One of the most effective image compressors we tried was Caesium. It’s simple, minimal, and can both compress as well as outright resize images. It’s also free to use.

Large Files Caesium Resize

Designed with simplicity, Caesium is not a jack of all trades and is a master of few: it supports only JPG, PNG, and WebP files, and has few settings. The lack of bloat makes this app incredibly intuitive to use as well as unobtrusive. Selecting images, renaming the files and choosing a destination location was easy. A surprisingly useful feature is the option to batch-resize images according to a short edge or long edge.

One potential downside is that it may not be able to resize very large images on computers with moderate specs. When we tried using this application to shrink our 40,000 x 20,000-pixel test image down, we got an “Insufficient memory” error on our laptop with 8GB of RAM. Another disadvantage is that the compression process (while successful at shaving 15 percent off the file size) took a good few minutes to complete.

6. Sumatra PDF

Sumatra PDF is a free, lightweight, and fast alternative to the bulky Adobe PDF viewer. It is tiny, weighing in at 20MB when installed, and has a portable single file version that can be executed from a flash drive.

Large Files Sumatra Read

A unique feature is Commands, available from the Command Palette (Ctrl + K), which makes navigating PDFs even faster. For our purposes, it excelled at viewing large PDFs.

Large Files Sumatra Command

In our tests, Sumatra instantly opened our large PDF test file containing over 1000 pages interspersed with images. Scrolling from top to bottom was a breeze, and we could instantly jump to different sections of the PDF by using the “Bookmarks” feature. This snappiness was a far cry from the long load times and scrolling at a snail’s pace that we experienced with other methods.

7. VLC

You most likely already know that VLC media player is packed with great features like advanced subtitle support, editing capabilities, extensive out-of-the-box codec support, and network playback. This free and open-source video player was also superb at rendering lengthy high-resolution videos according to our tests.

Large Files Vlc Video Playback

VLC’s playback of a ten-minute 4K (3840 x 2160) 60 FPS video was buttery smooth. Seeking forward and backward to random points of the video was almost instantaneous. Playback at faster speeds also performed admirably, as did playback with various VLC video effects and filters.

8. GOM Player

GOM Player, a freemium ad-supported media player, is another good option for playing high-resolution videos.

Large Files Gom Player Video Playback

We opened our 4K test video in GOM Player and found playback to be responsive. However, at times the frame rate dropped below the full 60 frames a second. Seeking was instantaneous, though – something that even VLC failed to achieve.

A drawback of this player is the annoyingly high number of ads. The installer tried to get us to install other software during installation more than once, and the video player itself was packed with ads, including a permanent one at the bottom of the player. These can be removed by paying a one-time $15 upgrade fee.

9. Excel’s Power Pivot

Large spreadsheet data is one of the trickiest types of data to handle. The official limit for Excel sheet sizes is 1,048,576 rows by 16,384 columns, according to Microsoft. But what if you need to work with data that exceeds that size? Amazingly enough, there is a built-in Excel feature that lets you not only open but also analyze very large data sets: Power Pivot.

Power Pivot successfully managed over 100 million lines of CSV data in our testing!

Large Files Excel Power Pivot Fields

When initially importing our test data, we made sure to select “Only Create Connection” and “Add this data to the Data Model.” Loading our large files took a while – several minutes – but Excel never became unresponsive, which was heartening. When it completed, we accessed Power Pivot via the “Data tab -> Data Tools -> Manage Data Model.”

Large Files Excel Ribbon Go To Power Pivot

This opened a new window where we scrolled down and viewed all 100 million lines of data – but that wasn’t all. We also added a new column with a formula that used values from two other columns and applied it to all 100 million rows. It worked without a hitch.

Frequently Asked Questions

Why can I still not open some large files?

While all of these programs will handle almost every file and make a big difference in the speed of viewing those files, good specs on your computer will also make a difference. You’ll want a decent CPU, enough RAM, and an SSD (not a slower HDD). A fast CPU and SSD help open a file faster. When the file is open, you’ll need both the CPU and RAM to be high enough to successfully view and manipulate the file.

Are these programs safe to download?

Yes, we tested all of these programs while running only Windows Defender and encountered no security issues. Additionally, almost all of these recommended programs are open-source software – this means the programs’ source code is publicly visible and can be checked for viruses or malware by the software community at large. If you’re technically inclined, you can download the source code and compile the program yourself, removing the possibility of the program developer sneaking something into the installer they provided you.

Why does opening a big file cause my whole computer to slow down?

This happens as a result of how the Windows pagefile (also called virtual memory) works.

When a file or program is opened, your computer consumes some RAM. The bigger the file, the more RAM is used. If all your RAM is in use, then Windows will resort to using your slower disk drive as extra RAM via “pagefile.sys.” While this allows you to have more programs open than your RAM can handle, it comes at a cost. Your computer will be pushed to the limit, continuously bringing active program memory from the pagefile into RAM while clearing less active program memory from RAM and writing it into the pagefile.

All of this consumes CPU cycles and disk read/write capacity, leaving less computational resources for the tasks you want to do. Since closing a program frees up RAM and potentially stops the pagefile process, closing open programs can sometimes dramatically speed up your computer.

All screenshots by Brandon Li.

Brandon Li
Brandon Li

Brandon Li is a technology enthusiast with experience in the software development industry. As a result, he has a lot of knowledge about computers and is passionate about sharing that knowledge with other people. While he has mainly used Windows since early childhood, he also has years of experience working with other major operating systems.

Subscribe to our newsletter!

Our latest tutorials delivered straight to your inbox