Why do you need a video card riser and how does it affect performance?
Computer assembly – a seemingly simple task. Take the components and simply connect them to each other inside the system unit. But there are situations when the video card, as the largest component, simply does not fit in the case or fits, but interferes with the normal cooling of the entire system. If you are not ready to change the case or replacing the case still does not solve anything in your case, you can use risers. We will tell you in this article what they are (in case anyone doesn’t know), how they are installed, what they are, and whether they affect the performance of video cards.
What is a video card riser
Raisers are devices that allow connect the video card to the motherboard not directly, but indirectly. They are usually used in situations where standard placement of the graphics accelerator is inconvenient or impossible. Thus, you can install it in a non-standard way: horizontally, vertically, at an angle or remotely. In essence, this is nothing more than an extension cord or adapter.
The riser is an optional accessory and is not required in every build. They became widely known after the mining craze. Necessity use several video cards in the assembly at once led to the popularization of extension cords. But their purpose is not limited to just this.
The benefits that the riser provides:
Provides flexibility in the computer layout process, which can be important when using compact enclosuressuch as Mini-ITX.
Allows you to increase the number PCI-E slotsif the motherboard’s own connectors are not enough.
Reducing the load on the motherboardbecause when using a riser, the weight of the video card no longer puts pressure on the expansion slot.
Improved air circulation and component cooling. This is especially true in systems with water-cooled video cards.
A typical riser consists of a printed circuit board with a PCI-E connector for connecting a video card and (if it is a riser with a cable) a flexible cable connecting this card to a slot on the motherboard. Its length can vary greatly, but the norm is from 10 to 30 cm. Thanks to this, the discrete GPU can be placed away from the PCI-E slot.
PCI-Express 3.0 vs 4.0
Video card connected via riser, will operate at maximum power only if the PCI-E versions of the extender itself and the motherboard of your computer match. If the interface generations are different, you may be in for an unpleasant surprise. Discrepancies can lead to the fact that the graphics accelerator, although it will start, will not reach “cruising speed”.
Backward compatibility of the riser and motherboard is everything to us. Components with different versions of PCI-E will work together, but at the speed provided by the earliest generation interface. If the motherboard has PCI-E version 4.0 and the riser has version 3.0 or vice versa, the system will not overclock faster than PCI-E 3.0 allows it. A PCI-Express 4.0 board simply won't be able to realize its full potential if it is limited by the 3rd generation standard.
PCI-E 3.0 riser offers throughput of up to 8 GT/s (gigatransfers per second) per line, which corresponds to approximately 985 MB/s in one direction. Thus, a full x16 slot can provide up to 15.8 GB/s. In turn, PCI-E 4.0 doubles these figures to 16 GT/s per lane, which gives approximately 1.97 GB/s per lane and up to 31.5 GB/s for the x16 slot. In addition, PCI-E 4.0 features reduced power consumption and improved data encoding efficiency.
Reduced graphics card performance due to an incorrectly selected riser, this can indeed occur. However, it all depends on your use case. In many cases the difference will be minimal and almost unnoticeable. If we are not talking about super-resource-intensive games and other similar cases, then PCI-E 3.0 bandwidth will be more than enough.
But professional applications that require processing large amounts of data in real time may be more demanding on the interface version. In their case riser with PCI-Express 4.0 will definitely be more advantageous than 3.0. This is true for programs that use the GPU for calculations, AI computing, and machine learning. For such scenarios, you definitely can’t screw up the riser.
What are the types of risers?
There are two types of video card risers: with a cable and without a cable.
Riser with cable
They are also called flexible. They use a thin and flexible cable that allows you to easily maneuver and place the graphics card in any position in the case. It is these risers that serve as extension cords. Thanks to them, you can place the discrete GPU away from the motherboard.
Rigid risers, or risers without cable
This type of riser features a rigid base on which the video card is mounted, which provides greater reliability when placed inside the system unit and often better throughput due to the absence of wires, which can affect performance.
Such risers, as a rule, serve to change the orientation of the video card (but not necessarily):
Vertical risers are used for, surprise, vertical installation of a video card, which is important for the “display” type of video card placement in display cases with a transparent side panel, and at the same time to improve air cooling.
Horizontal risers are used for the standard location of the card in a horizontal orientation, but at some distance from the motherboard. This type of placement may be relevant when using narrow or other non-classical buildings.
Corner risers – This is another type of riser for video cards, which allows you to change the orientation of the graphics accelerator inside the computer case. Unlike vertical and horizontal risers, corner models allow the video card to be rotated 90 degrees relative to its original position.
The influence of the riser on video card performance
Using risers for video cards can really affect system performance. But this aspect can be viewed from two sides: positive and negative.
The factors of the positive influence of the riser are already on the surface. It allows you to place the video card in such a way that it does not interfere with other components and can better heat dissipation. In this way, the negative effect of high heat generation can be reduced. Proper placement of the video card, in which it does not interfere with the removal of hot air, will have a positive effect on the temperatures inside the assembly and the stability and performance of the entire video card system.
The negative impact of risers is less obvious, but also quite understandable. The following aspects can cause it:
Workmanship. Raisers assembled from low-quality components can cause unstable operation of the video card and reduce its performance. Cheap or easily damaged cables often lead to signal loss, image artifacts, and even complete video card failure. To avoid compatibility and reliability issues, choose reliable solutions from reputable providers. Reliable brands include Thermaltake, Lian Li, Deepcool, etc.
Length of cable. Excessively long risers can also potentially cause delays in signal transmission between the video card and the motherboard, which negatively affects performance. According to studies, using a 50 cm long riser can lead to a deterioration in the throughput of the video card. However, most often these are completely uncritical figures: only about 2-3% compared to a direct connection.
Compatibility. We have already discussed above that the PCI-Express version can be of great importance for the correct operation of a video card connected via a riser. Using a power strip that is not fully compatible with the GPU or motherboard may result in poor performance or even an inability to boot the system. This is especially true for the newest cards that require PCI-Express 4.0 standard support.
Interference. The negative effect of placing the riser near sources of electromagnetic interference, such as the power supply or other cables, is considered last. But even this can lead to signal distortion and, as a result, small drawdowns in the performance of the video card. Therefore, when routing the riser, it is important to consider its location and, if possible, place it away from potential sources of interference. Shielded cables, ferrite beads, and other protective measures can be used to minimize the impact of electromagnetic interference.
Features of use in systems with several video cards. When using risers in configurations with multiple video cards (for example, SLI or CrossFire), additional problems may arise related to compatibility, synchronization, and load distribution between graphics accelerators. In such cases, it is important to use identical risers for all video cards and ensure their correct connection and configuration.
Simple rules that will help you avoid the problems described above:
Use only high-quality risers from trusted manufacturers.
Choose risers with the optimal length for your build.
Take into account the characteristics of the riser, which must correspond to the technical design of the video card and motherboard.
Place the riser away from sources of electromagnetic interference.
When installing the riser, follow the manufacturer's instructions and pay attention to the correct connection of all cables and connectors.
Ensure optimal placement of the video card and cables inside the case, taking into account cooling and air circulation features.
There is an opinion that the riser itself, regardless of the cable length, almost always eats away part of the video card’s computing potential. However, the results of professional tests and benchmarks in games and other applications have shown that the difference in performance between directly connecting the video card to the motherboard and using a high-quality riser is within the measurement error.
Thus, in Tom's Hardware tests using an NVIDIA video card GeForce RTX 3080 and the Thermaltake TT Premium PCI-E 4.0 riser, the difference in performance in games and synthetic tests did not exceed 1-2%. Similar results were obtained in other independent studies.
An alternative to using risers There may be special extension cables or adapters for video cards. They also allow you to change the position of the video card inside the case, but, as a rule, provide less flexibility compared to full risers. Additionally, the quality and compatibility of such cables and adapters may vary by manufacturer and model.
Thus, risers for video cards are a useful accessory that allows you to improve cooling and optimize the internal space of the system unit. When using high-quality components and following compatibility rules, the influence of the riser on system performance is minimal. The main thing is to choose proven solutions from reliable manufacturers, take into account the features of your assembly and follow expert recommendations for installation and configuration. And then the riser will become your reliable assistant in business creating a powerful and efficient gaming PC.
