Do GPU Riser Cables (Extension Cables) Reduce Performance?

PC cases are getting smaller at a time when GPUs keep getting bigger, often resulting in people needing to buy GPU riser cables to squeeze everything into their PC build. But if you’ve started having bad performance or FPS rates, you might be wondering whether your riser cables are to blame. Let’s dig into whether they can reduce performance or not.

Recap: What Are Riser Cables?

PC hardware is rapidly approaching a point where we can’t eke out more performance from the same size transistor (leading people to ask whether Moore’s Law is dead). As a result, graphics card makers have started making them a ‘bit’ bigger instead:

Yes, NVIDIA’s flagship RTX 4090 GPU is actually bigger than entire gaming consoles! This presents a problem for PC builders, because we don’t all have room for massive cases. Heck, even bigger cases like the Lian-li O11DXL can struggle to fit the RTX 4090 – which seems a bit crazy to me.

One solution to this growing problem is to buy PCIe riser cables, also sometimes called PCIe extension cables. These allow you to move the location of your graphics card, which otherwise would have had to be installed in your motherboard’s PCIe slot and then attached to a certain point of your PC case:

The PCIe case screw holes where the GPU is screwed in to
Where the GPU is screwed in to

That’s where PCIe riser cables come in – they plug into the motherboard’s PCIe slot, and then allow you to move your GPU to another place (you can ‘rise’ it above the original slot):

A PCIe 3.0 riser cable from Thermaltake
A PCIe 3.0 riser cable from Thermaltake

Can These Extension Cables Reduce Performance?

Do these kill GPU Performance

In general, a high quality PCIe riser cable will not impact GPU performance at all. However a low quality PCIe extension cable might cause issues, as will using a PCIe 3.0 riser cable with a modern PCIe 4.0 graphics card. People also sometimes blame riser cables even though other issues or bottlenecks are the actual cause of poor graphics performance.

That’s the high level answer, but let’s dive into the detail a bit more – especially because PCIe can be a confusing topic, because you have to consider:

  • PCIe generations – such as PCIe 3.0 (generation 3) and PCIe 4.0 (generation 4). Each new PCIe version (i.e generation) brings better performance, with PCIe 4.0 offering a theoretical doubling of performance compared to PCIe 3.0.
  • PCIe lanes – this is the physical component link between the motherboard and CPU, where “PCIe x1” means one PCIe lane and “PCIe X16” means 16 lanes. More lanes means more bandwidth, effectively meaning more performance potential.

This is an important point, because the following riser cable will definitely harm your performance if used with a modern GPU:

A PCIe 3.0 X1 riser cable on AliExpress
A PCIe 3.0 X1 riser cable on AliExpress

While there’s nothing specifically wrong with that riser cable (i.e. I assume it’s a high quality and well built cable), the fact that it’s a PCIe 3.0 cable and it only uses one PCIe lane (“X1”) means that it will inherently limit the performance of a modern GPU that is almost certainly PCIe 4.0 x16.

That particular riser cable is probably designed to reposition an older PCIe 3 SSD, and not a high performance GPU.

Key Point: You should always ensure that the PCIe riser cable you use matches the PCIe generation and lanes of your graphics card. For example if you have an RTX 4080 (which is PCIe gen 4 and runs at x16), you will need a modern PCIe 4.0 x16 riser cable – otherwise the riser cable will limit your graphical performance.

Secondly, if you purchase a really budget, no-name PCIe extension cable then there’s no guarantee that it will run at the stated performance. Not to hate on AliExpress, but can you say for sure that these cables are all 100% performant?

A range of PCIe risers from AliExpress
A range of PCIe risers from AliExpress

I don’t mean to bash AliExpress (they can be a great resource for certain equipment), but some of the PCIe riser cables they sell have minimal (or zero) reviews – and they haven’t undergone extensive third party testing. So even if you do purchase a “PCIe 4.0 x16” cable from there, you can’t be completely sure that it will run at the stated speeds/specifications.

If you have an expensive GPU, I would always purchase a quality PCIe riser/extension cable from a reputable online retailer (which also excludes Amazon, who have a growing problem with fake products). Companies like LINKUP, Lian-li and Thermaltake all produce good quality riser cables, but naturally always double check the reviews for the specific product you plan to purchase.

A high quality PCIe 4 riser cable from LINKUP
A high quality PCIe 4 riser cable from LINKUP

Side Note: If you’re interested in learning more about the performance of riser cables, there was an awesome post on the Overclock forum that did quite detailed testing on five riser cables of varying length and quality. In their testing, there was barely any performance difference between using riser cables or not. Some people also say that unshielded cables can cost performance over a certain distance, but their testing didn’t conclude this either.

Factors That DO Affect Graphical Performance

Gameplay screenshot from Starfield
Gameplay screenshot from Starfield

So we now know that if you are experiencing worse graphical performance, it’s unlikely to be caused by your riser cables. But what can be causing the performance drops? Well this topic could be an entire article in itself, but the most common things to check are:

  • Ensure that your graphics card drivers are up to date. They can sometimes become buggy, and I often find that uninstalling and reinstalling the drivers can improve weird graphical issues like low performance.
  • Maybe the game itself is buggy. An increasing number of PC games are shipped out too quickly, resulting in a range of bugs and low FPS rates. It’s also worth checking if there are any pending updates for the game, or searching online to see if the game has known bugs with certain hardware.
  • Is your case or cooling inadequate? If your case is too small and/or doesn’t contain adequate cooling, your GPU or CPU might be being thermal throttled. This means that your computer’s hardware is running at a slower speed than it should be, which will naturally result in lower performance. Check that all your case fans work as expected, and also consider upgrading from air to liquid cooling for your processor and graphics card.
  • Are any updates or virus scans running in the background? Windows Updates and auto-scheduled virus scans can kick off at inconvenient times (like during a gaming session), and these can often result in lower gaming performance. It’s worth pausing such updates and scans until after you’ve finished gaming.
  • Maybe your computer simply can’t play the game at its current settings? Some modern games require a massive amount of VRAM to run, especially at higher resolutions like 4K. If you find that your CPU and GPU are maxed out when gaming, you might simply need to lower some of the graphical settings (or your resolution) in order to play the game smoothly.
cropped A picture of me Tristan
About Tristan Perry

Tristan has been interested in computer hardware and software since he was 10 years old. He has built loads of computers over the years, along with installing, modifying and writing software (he's a backend software developer 'by trade').

Tristan also has an academic background in technology (in Math and Computer Science), so he enjoys drilling into the deeper aspects of technology.

Tristan is also an avid PC gamer, with FFX and Rocket League being his favorite games.

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