By Ellie Twitter / Last Updated April 26, 2023

VNC is very slow

"Hello all, We have been using TightVNC and LanSchool to log in to our computers to work on systems remotely for our teachers and have had problems with the remote connection "blacking out" after just a few seconds.  This is extremely annoying and is happening on most of our computers.  Why is VNC very slow on Windows? Any suggestions on how to make it faster?"


Why is VNC so slow?

VNC basically transfers data between the VNC Server and VNC Viewer by taking a number of screenshots, compressing them, and sending them over the network. It cannot be compared to streaming video. In video streaming, a pre-compressed video stream is typically transferred over the network. HD streams are frequently H.264 encoded. When using VNC, your host computer is required to take screenshots, compress them, and then send them over the network. Here, there are several limitations:

  • Strong compression necessitates a significant amount of CPU power. Encoding a 90-minute movie in H.264 at high quality, for example, can take more than 4 hours on my Athlon X2 4450e server. Such strong compression is typically unsuitable for real-time applications such as remote control.
  • Less strong compression will necessitate more network bandwidth, which may be an issue on low-bandwidth connections such as the Internet.

That's why VNC is so slow.

How to make VNC faster [4 solutions]

VNC, a screen-sharing tool, allows users to remotely access the PC as though they are sitting in front of the PC. However, some users complained that VNC is very slow on Windows 11, 10, and 8...  If you have the same issue, keep reading to realize why VNC is slow and how to improve the performance of VNC. 

Solution 1. Change the encoding options on the local PC

It is said that changing the encoding options to “Tight” when the PC is working over constrained bandwidths will make the VNC faster.

Step 1. Open VNC and then locate “Connection Options”.

Step 2. Under the “Format and Encodings” tab, change the Preferred encoding to “Tight”. Click on “OK” to apply.

Preferred Encoding

Note: If the VNC Server is on your LAN, we recommend you to use “Raw”, which may be better and faster.


Solution 2. Turn on JPEG compression on both 2 PCs

When you use VNC, the host PC has to take screen snapshots and compress them, which needs a lot of CPU power so that the VNC is slow. According to some users, the “VNC very slow” can be fixed by using JPEG compression.

Step 1. Open VNC and then find or directly enter the IP address of the host PC.

Step 2. Tick “Use JPEG Compression” and then select “Connect”.

Use GPEG Compression

Step 3. Now the connection can be faster

Solution 3. Change the resolution settings on both PCs

To a large degree, the higher the resolution the more bandwidth and CPU power needed to send updates. For this reason, changing the resolution of VNC on the two PCs can speed up the VNC.

Step 1. Go to VNC, and then find “Display Preferences”.

Step 2. Change the “Resolution” to the lowest. And then click on “Apply”.

Change VNC Resolution

Solution 4. Disable scaling and adapt to network speed

It’s recommended to change the scaling to “No scaling”; then the CPU power will have more space to improve your remote connections, which means the speed of VNC will be highlighted.

Step 1. Go to VNC and choose Options.

No Scaling VNC

Step 2. Under Scaling, tick “No scaling” and then choose “Adapt to network speed”. Click on “OK” to apply the settings.

A fast & free VNC-based remote desktop software: AnyViewer

After trying the solutions above, is your VNC still very slow? According to the feedback of some users, they found that VNC is still laggy even though they take much effort into fixing it. Here, we recommend using a fast VNC-based remote desktop software - AnyViewer.

  • Free. AnyViewer provides completely free services for individuals and businesses.
  • Easy. AnyViewer also serves remote control and access for the users. Compared to VNC, the operation and installation of AnyViewer are easier and more time-saving.
  • Fast. The fast connection speed and high responsiveness ofAnyViewer on both two PCs will guarantee the best feelings for the users.
  • Safe. AnyViewer is secured by Elliptic Curve Cryptography (ECC) end-to-end encryption.
  • Flexible. AnyViewer is supported by flexible connection methods. For unattended access, you can realize remote access with one click.
  • Compatible.AnyViewer is workable for Windows 11/10/8.1/8/7 and Windows Server 2022/2019/2016/2012 R2.

Click on the Download button to get AnyViewer.

Download Freeware Win 11/10/8.1/8/7/Server
Secure Download

Step 1. Install and launch AnyViewer on both computers. Go to Log in, and then click Sign up. (If you already have signed up on its official website, you can log in directly. Fill in the signup information to create an AnyViewer account.

Step 2. Then you can see you successfully logged in to AnyViewer. Your device will automatically be assigned to the account you've logged in to.

Free Editions

Step 3. Log in to the same AnyViewer account on the two devices; then you can achieve a direct connection by clicking One-click control.

Connect to My Devices

After successfully connecting to another computer, you can enjoy a fast connection, and it's available to remotely view files, access programs, open browsers, etc. Besides, AnyViewer also allows you to remotely access multiple computers simultaneously without any lag and delay. But you need to upgrade your account to the Professional or Enterprise edition. 

One to Many Support


Are you still encountering “VNC very slow” on Windows 10, 11, 8, and 7...? By changing some settings in light of the solutions above, such as changing the encoding options and resolution, the performance of VNC should be improved. But if you are still running into “VNC very slow” when you start your remote session, I think AnyViewer is the best one that is suitable for you.


Q: Is RDP safer than VNC?

A: RDP is more secure than VNC as VNC doesn't encrypt the entire session. 

Q: Why is VNC slower than RDP?

A: RDP uses Windows' drawing graphic primitives, while VNC is a raster/pixel protocol. The data through VNC is transferred across the network in what is essentially called an image exchange, which makes VNC slower than RDP.

Q: What is faster than VNC?

A: RDP is typically faster than VNC.

Q: Does VNC use a lot of bandwidth?

A: Yes. VNC needs more bandwidth than RDP as it's oriented at duplicating the pixels of the remote display.