What is ideal internet speed for remote desktop connection?

Question

My question and situation is similar to Recommended Connection Speed for Remote Desktop question but I need a little more info.

I know that lag can be a factor in working on remote desktop. Lets ignore that. My question is about is the ideal data rate for a good remote desktop connection.

Assume that my RDP is 1080p display. I am using external monitor that is 1080p as well.

The number of pixels in 1080p are

1920 * 1080 = 2,073,600 pixels.

Each pixel uses 16bits of color (2 Byte). Thus the number of bytes used by one screen is

(2,073,600 bit ) * 2 Bytes = 4,147,200 Bytes or ~ 4MB

Since the screen is refreshed at least 10 times a second (lets assume 10 here), the refresh rate required for smooth connection would be = 4MB*10 = 40 MB/Sec

Does these numbers make sense? Does RDP uses something better than this because that is a lot of bandwidth?

Does the size of monitor at RDP end make a difference at the connection? Bigger monitor takes more bandwidth than smaller one?

Answer 1

In Remote Desktop Connection (RDP), The Server does not actually sends the screen to the client screen. That process is quite expensive as you have to constantly poll the screen for any changes which can be easily +7MB of data. RDP uses special protocol. It basically uses virtual screen. It kind of interacts with the graphic card. In stead of sending screen to the actual one, it send screen content to a virtual screen.

This article and this by by Nadim Abdo of Microsoft explains it very well. It talks about all the myths about RDP. The following is an bandwidth graph from the article

Typical high bandwidth of RDP is 130 Kbps (Kilo bits per second) Typical low bandwith of RDP such as scrolling etc is about 5kbps.

Note that my problem is mostly with scrolling and switching tabs in firefox. Since I have 4Mbps speed (3.6Mbps effective), this should not be a problem. I am assuming the slow speed that I am getting is because of my server computer which at times does get slow and I know is not the fastest machine on the planet.

Answer 2

The full screen is not refreshed every 10 seconds. The speed of remote desktop responses will depend on the graphics settings, local devices brought over, whether printers are local or remote, audio settings, and many other factors.

But the bottom line is that the "ideal" speed for remote desktop is "as fast as you can afford".

I agree with you that the biggest issue is often with the browser, but most often I see that if the browser opens a page with an animated graphics file or flash video. I'd suggest that if you plan to use a browser when in an RDP session, disable the display of animated graphics, and perhaps even disable flash.

Answer 3

After going through all, in brief I'd mention that for a good RDP, you need to have good and consistent latency, say below 50 Ms. While bandwidth upto 2 Mbps per client PC is ideal. Further, all the configurations present in the option of Remote Desktop Connection must be lowest.

In case ping in Ms fluctuates much, say sometimes 40 Ms, immediately after this, 200 Ms, then in such case your RDP experience is not going to be good.

Speed, i.e. bandwidth is not a factor. Accordingly 2 Mbps speed at the client end is sufficient. Latency is important. Further, the upload speed at the end of the server is very important.