How expensive the services of render farms are.

In my opinion, pricing is one of the most important aspects in the selection of a service provider (important to view 3D configurators without problems) who provides services as a render farm. So let`s look at how render farm pricing works.

What is a GHz hour? What are core hours about?

You have probably seen some online render farms that display a price per GHz hour or per core hour for their render time. It`s a system that can be confusing for a first-time user. They usually do this because they have servers from multiple hardware generations and because hardware performance is uneven, they try to find a common denominator for a pricing strategy.

As a result, these two unity require some effort and attention from users to calculate the price correctly.

In a price calculated in GHz hours, they measure their computing time as the sum of the GHz hour of the servers you are using.

Example: You use one server for two hours. The server has a 6-core CPU. Each core has 2.4 GHz. The price per GHz hour is €0.16. The following you have to pay for it:

6 x 2.4 x 2 x €0.16 = €4.60

If the server has two identical CPUs, the price doubles.

The price model based on core time is very similar. They are charged according to the number of cores in the server. So for the same server that has a 6 core CPU, you will pay a total of €0.5 per core hour for two hours of use.

6 x 2 x €0.5 = €6

Why do I think this model isn`t good?

First of all, it`s hard to understand. That`s why it`s difficult to estimate the cost of rendering. Also, the defintions can be ambiguous or misleading. Let me go into this subject a littler further.

• Not all cores have the same structure. For example, take two Intel server CPUs from the Xeon line: Xeon X5670 @ 2.93 GHz and Xeon E5-2667 @ 2.90 GHz. They have the same number of cores and almost the same core speed. You will notice that the second is 23% faster than the firstm even if it has a slightly lower frequency. The first is from the 2010 generation and the second was released in 2012. In addition, the AMD Opteron 8439 SE @ 2.80 GHz CPU has almost the same features as the two Intel CPUs in terms of cores and speed, but its performance is only half that of the Xeon X5670.
• The definition of a core can vary from operation to operation. Some of them don`t even say what kind of machine they have, but only the number of cores and the core speed. For example, one of the render farms says that you have Xeon 8 core. And 12-core machines with 3.0 GHz speed have, while another says that they have Intel Xeon E5645*2, 16 cores. Some of the render farms consider a hyperthreaded core as two separate cores, so you`ll have to be careful.
• The same goes for the GHz hour. If you compare the two Intel CPUs to the above, a GHz from the second machine is 23% faster than a GHz from the first machine. So the actual value is 23% higher. If you switch to the AMD CPU, the same GHz has only half the power.

What does all this mean?

What looks like the better price doesn`t always have to be the better solution in the total bill. You can get more renderings per euro from a render farm that seems more expensive, but in the final bill gives you more power for the same amount. So you should never neglect hardware aspects.