Best PCIE Riser & Extension Cables for heavy GPU Workloads

CG Director Author Alex Glawion  by Alex Glawion   ⋮ 
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Best PCIE Riser & Extension Cables for heavy GPU Workloads

In recent years, manufacturers have been designing more and more innovative PC cases. Not long ago, an ATX case was an ATX case. But now, you’ve got many more options to choose from.

One good example of this is internal storage. As recently as 2010, the standard for internal storage was a large, front-mounted rack designed for 3.5” drives. And, to be fair, 3.5” drives are still common. But now, 2.5” SSDs are also used alongside them.

Moreover, many PCs now use M.2 slots to mount the SSD directly on the motherboard, eschewing a traditional front-mounted design.

As storage has gotten smaller, so have cases.

Now Mini ITX and Micro ATX cases are becoming more and more common.

On the other hand, PC-User’s have been able to take advantage of the additional space that was formerly used by 3,5″ and 5,25″ Dives and use it for AIOs (All-In-One Liquid Cooling) or mounting custom watercooling and pumps to the inside of the case.

Why Use a PCIE Riser?

We’ve already talked about why you might want to use a PCIE riser, but let’s sum up. There are two main reasons why you might want to do this:

  • Space constraints: Better / Possible GPU placement for Single- or Multi-GPU Configurations & possibly better cooling
  • Aesthetic Reasons: Showing off your GPU in other orientations
PCIE Riser Cable

Image-Credit: Thermaltake

There is one Component that has not kept up with the minification of many PC-Parts: the GPU.

By their nature, GPUs are still fairly large and bulky. They have built-in fans that require a certain amount of space.

And while smaller circuitry has become more efficient, the growing demands on a modern GPU have meant that each generation, manufacturers concentrate on making their GPUs more powerful at the same dimensions, rather than developing smaller GPUs.

The reason for this is obvious.

For gamers, content creators, and cryptocurrency miners, the GPU is a crucial aspect of your system. If you’re forced to choose between a faster GPU at the same size or a smaller GPU with less performance, faster is always better.

If you’re building your own PC or upgrading an older system, this can be a major inconvenience. Getting the right placement for your case fans, in particular, can be difficult task.

This is especially true if you want to overclock your GPU and other components.

Sometimes, it’s easier to relocate your GPU than relocate a fan. This is where a PCIE riser or extension cable comes in. Essentially, they allow you to move the GPU to a different location inside your case. You can put your GPU closer to your water block if you have a liquid-cooled PC, or up against the case’s window for maximum visual impact.

This is especially true for multi-GPU systems. If your motherboard will support it, running multiple GPUs will dramatically improve the performance of many workloads such as GPU Rendering.

For Multi-GPU configs, the spacing of the pcie-slots on the motherboard will often be sub-optimal to mount all of your GPUs directly.

But a graphics card is only as good as its connection to the motherboard, so let’s find the best PCIE risers and extension cables to meet your needs.

What’s the Difference Between Different PCIE Standards?

PCIE slots come in different sizes (lengths). The longer the slot, the higher the bandwidth supported.

GPU’s have high bandwidth needs and usually require the longest type of pcie-slot – x16 pcie-slots.

The yellow pins at the bottom of this GPU plug into the pcie-slot of a mainboard.Nvidia RTX 2070

Image-Source: NvidiaNow, x16 is not a fixed bandwidth, but depends on the generation of the PCIe interface we are talking about.

As you can see in this table, x16 on a PCIe-2.0 Generation is half as fast as x16 on PCIe-3.0.

PCIe BandwithBandwidth x1 (per lane)x4x8x16
PCIe 1.0250 MB/s1.00 GB/s2.00 GB/s4.00 GB/s
PCIe 2.0500 MB/s2.00 GB/s4.00 GB/s8.00 GB/s
PCIe 3.0984.6 MB/s3.94 GB/s7.88 GB/s15.75 GB/s
PCIe 4.01969 MB/s7.88 GB/s15.75 GB/s31.51 GB/s

Nvidia’s RTX 10xx and 20xx generation GPUs for example run on PCIe-3.0 and require a “mechanical” x16 pcie-slot.

Why mechanical? Because you can differentiate between a x16 slot which is mechanically long enough to fit x16 GPUs, but might “electrically” be slower and only transfer Data at x8, or even just x4 speeds.

If you’d like to learn more about this, do check out our GPU articles here and here.

So long story short, for PCIe-Riser cables, you’ll have to know a couple of things before you can start shopping for one:

  1. Know the required electrical Bandwidth of your GPU(s) (e.g. x16 PCIe-3.0)
  2. Know the required mechanical slot type required by your GPU(s) (usually x16 too)

There are cases when GPUs, although they are both x16 mechanically and electrically, aren’t fast enough to saturate the Bandwidth of a x16 pcie-slot.

Anything lower than an Nvidia 2080 Ti for example, will perform the same on both a x8 or x16 PCIe-Slot. This is because the GPU’s Bandwidth is not high enough to saturate (be faster than) the bandwidth of a x8 PCIe-Slot.

What Should I Look For in a PCIE Riser?

So, what makes a PCIE riser worth buying? There are a few different factors you should look for.

There are two main types of PCIE riser: powered and unpowered.

Powered risers utilize a secondary power supply to supply power. This is usually an internal USB connection, but it can also be SATA or even MOLEX. Generally, powered risers connect to an x1 or x4 PCIE port and have an x16 adapter for the GPU. As a result, they’re usually used by crypto miners.

The reason is simple: Although the GPU-facing Slot has a mechanical x16 Interface, the Motherboard facing connector only is x4 and therefore can’t transfer at higher speeds than x4 Bandwidths.

This is only right for you if you know you won’t need higher Bandwidths than x4. Usually just miners or very un-demanding workloads can get away with this.

If you’re buying a powered riser, it’s a good idea to look for USB 3.0 support. This makes it easier to connect to your motherboard. In addition, look for the number of capacitors. The more capacitors, the more stable the power supply. Look for a riser with at least three capacitors to get the best performance.

PCI-E 1x to 16X Powered Riser Card w/ 6-Pin PCI-E Power & Enhanced ...

Un-powered risers, as the term implies, do not draw power from an external source. These risers draw power directly from the motherboard’s native x16 PCIE port. Typically, these risers are simple extension cables.

Un-powered Riser Cables

Image-Credit: Phanteks

I’ve Heard of M.2 Adapters – Are They Any Good?

If you’ve been shopping around for a PCIE riser, you may have heard of an M.2 adapter. Typically, an M.2 adapter is used for internal accessories such as an SSD. But you can also use them for lower-tier graphics cards if you use an M.2 adapter.

P4SM2 (PCIe X4 to M.2 Adapter)

Installing an M.2 adapter is generally very easy. You simply plug them into your M.2 slot, screw them down, and connect the SATA cable. It doesn’t get much easier than that.

Unfortunately, M.2 adapters are not suitable for content creation or gaming. The reason is that the M.2 slot has a data transfer rate equivalent to an x4 PCIE slot. This is just fine for crypto mining, but it’s not good enough for more demanding tasks.

Are Mining Motherboards Any Good for Content Creation or Gaming Workloads?

With the growth in popularity of crypto mining, some manufacturers have started releasing motherboards with a large array of PCIE ports. For example, check out this ASUS motherboard, with a single x16 slot, and a whopping 18 x1 slots for connecting a large GPU array.

No-Riser Motherboard

Image-Credit: Asus

Obviously, these x1 PCIE-Slots are a terrible choice for content creation or gaming as you’ll need much higher bandwidths for decent performance.

Of course, of you do both, Mining and Gaming for example, having a Motherboard with a single x16 slot with a GPU in it for Gaming, and a bunch of Mining GPUs attached to the x1 Slots would be a possibility.

What Are Extension Cables?

An extension cable is just another type of riser. Instead of a bracket, they’re just a simple male to female PCIE cable.

Extension cables are designed to allow for more flexible placement of your GPU. They’re ideal for maximizing your cooling system’s performance. If you’re a content creator or gamer, this is the type of “riser” you want to invest in.

For example, suppose you’re building a multi-GPU system for gpu rendering. By spacing the GPUs further apart from each other you would be able to keep the Temps lower, enabling longer boost and higher clocks on your GPUs – resulting in shorter render times.

PCIe Extension Cable

Image-Credit: Thermaltake

When you’re buying an extension cable, longer is not always better. To be fair, a longer cable gives you more options for GPU placement. On the other hand, it presents some challenges for cable management. A shorter cable, on the other hand, requires less cable management.

Longer cables can also decrease the quality of the signal that is transferred (Impedance), so be sure to get as short a cable as possible, especially when you are in need of high bandwidths.

Will a PCIE Riser Affect My Performance?

Provided you use a quality riser cable and handle it carefully, it will not affect your performance negatively. That said, there are a few caveats to that.

  • If you’re daisy-chaining PCIE cables, you may run into some power supply issues. This will depend on how well-engineered the cables are. For gaming or content creation, this won’t be an issue, since everything is presumably inside the case. But if you’re putting together a GPU array for crypto mining, check the manufacturer’s ratings for daisy-chaining.
  • Another potential issue is the quality of the locking mechanism. Make sure the lock is nice and sturdy, and keeps the plug securely in place. If the lock is flimsy, you might end up breaking it during installation. Needless to say, this can really ruin your day.
  • Finally, a good magnetic shield can be a great help. If the cables are shielded with TPE, this will go a long way towards reducing interference from any nearby sources of interference.

PCIE Riser/Extension Cable Recommendations

We’ve talked about all the basics. Now, it’s time to take a closer look at our top pick. We’ve gathered our recommendation and two alternatives, so you can choose the best one for your purposes.

Let’s take a closer look!

Highest Quality PCIe-Riser Cable – Thermaltake AC-045-CN1OTN-C1

Thermaltake PCIe Extension Riser Cable

Image-Credit: Thermaltake

One way to find the best PCIE riser is to go with a manufacturer you know and trust. For fans of high-end PCs, Thermaltake should be a familiar name. They’re primarily known for their top-notch cooling systems and RGB lighting rigs. But they also make some excellent cables.

The Thermaltake is a PCI-E x16 3.0 Cable which will enable the full Bandwidth for your PCIe-3.0 GPUs.

The riser cable measures 30cm in length, making it a great choice for long runs. The cables are housed in five separate ribbons, which allows for better shielding than a single ribbon. Each ribbon is encased in a layer of TPE plastic shielding, with additional PE insulation on the individual copper wires. This allows for full use of the PCIe-3.0 Bandwidth, with virtually zero interference.

In addition to being well-insulated, the Thermaltake ribbons are also very flexible. Because they’re separate from each-other, they can make multiple bends and twists. Even if your PC case is very crowded, cable management is going to be a non-issue.

Thermaltake PCIe Extension Riser Cable inside case

Image-Credit: Thermaltake

Both the male and female connections on the Thermaltake are gold-plated, ensuring excellent conductivity. And the PCBs are beefy and robust. The clip on the female end is nice and fat, which makes it easy to snap shut. As a result, you’ll get a secure, stable connection without a lot of faffing about.

All of this is guaranteed by Thermaltake’s one-year manufacturer’s warranty. Thermaltake is well-known for excellent customer service, so you’ll have no issues there. This cable may be on the expensive side, but it’s by far the best PCIE riser on the market.

Runner-Up: Phanteks Premium Shield Riser Cable

As an alternative to the Thermaltake Riser Cable, our runner up is the Phanteks 600mm Premium Shielded PCIE Riser Cable which has a similar 90-degree tip. However, it’s a full 60cm in length, perfect for very long runs. To ensure signal integrity at this length, it sports shielded twin-axial wires, along with dedicated power lines.

Alternative: LINKUP Shielded Twin-axial Riser Cable

That said, a 90-degree tip can sometimes make cable management easier. In that case, the LINKUP Shielded Twin-axial Riser Cable is an excellent choice. And with hand-soldered gold plated contacts and five shielded ribbons, you’ll get a fast, clear signal.

For those of you sporting a PCIe-4,0 GPU like the newer AMD Radeon RX5700XT, LINKUP has updated their cables to support full PCIe-4.0 x16 Bandwidth with their newest models.

 

That’s about it from my side! Let me know your questions in the forum or in the comments! 🙂

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Alex Glawion - post author

Hi, I’m Alex, a Freelance 3D Generalist, Motion Designer and Compositor.

I’ve built a multitude of Computers, Workstations and Renderfarms and love to optimize them as much as possible.

Feel free to comment and ask for suggestions on your PC-Build or 3D-related Problem, I’ll do my best to help out!

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