Bandwidth and Speed are very important when discussing the construction of a HDMI® cable. One has to have a general understanding of how these two words pertain to cables as well as how they play into the cables functional capability. Bandwidth and Speed are a very difficult and confusing concept for most people to grasp.

What is Bandwidth? What is speed?

Although bandwidth and speed have much in common, they are different and are frequently and incorrectly used by both consumers and the manufacturers to express the same thought.

• Bandwidth refers to how much data can pass thru a device at the same point and time.
• Speed refers to how quickly a device can create the data.

For example, when discussing the differences in bandwidth needed to produce a 1080P picture (5 Gbps by Spec) and a 4K/60, 4:2:0 picture (9.2 Gbps +/-) what we are really comparing is the width of the high-way and the number of available traffic lanes. Think of it this way: You send a 100 vehicle convoy between two cities down a 2 lane road at 60 miles an hour, this will give you 2 columns 50 trucks deep. The last truck in line will not arrive at the same time as the first. Now we increase the road to 10 lanes across and we are only 10 trucks deep closing the time gap. In widening the road, the trucks can now go faster and vehicle speed increases to 120 mph. A 10 to 1 increase in traffic flow is the result.

The trucks become data and you get our point – wider bandwidth increases the speed of the data in a HDMI cable.

What does this have to do with cables and why is this part of our series?

How fast a HDMI cable sends data is one of the most important facts of a cable and in our opinion must be a part of this series. There is not one physical part of a cable that increases bandwidth and speed. Wire gauge and consistency of the twist ratio determine both speed and bandwidth. Better quality product equals better data transfer. A cable must be well built to be able to produce wider bandwidths and increasing speed. DPL certification on HDMI cables is a good way to know if the cable will provide the best bandwidth and speed.

DPL certification is neither quick nor cheap. First it takes a while to design and build a cable that meets the DPL standards. Second in order for DPL to maintain “Truth in testing” on going testing is required and DPL does not get this samples from the vendor they come from dealers or distribution, so like “UL” certification there is a yearly fee to keep you (the vendor) up to date.

For the dealer, this is a fantastic resource as well as a great and timely report of what is tested and real.