Traditionally, when you need strong PC gaming performance, it has meant that a desktop was your only option. However, the advent of modern high-speed external interfaces such as Thunderbolt made it possible to integrate desktop-class graphics cards into laptops. These products, known as eGPUs, provide an easy way to provide enhanced graphics performance to laptops without discrete graphics. Basically, you put a desktop GPU in a special box and then connect that box to your laptop. The laptop then sends programs that need a lot of graphics to run on that box.
All eGPUs on the market currently use the Thunderbolt interface. Intel and Apple developed Thunderbolt as a fancy packaging of the PCIe and DisplayPort interfaces in an external cable. This enables a connection between PCIe devices and Thunderbolt-enabled laptops with a single controller chip.
To put this design into practice, today we're taking a look at Razer's Core X external GPU case. Of course, you'll need a compatible laptop to use the case. So we're using the recently reviewed Razer Book 13. Note that Thunderbolt and PCIe are industry standards, and you can use any eGPU with any supporting laptop. There is no vendor block between Razer laptops and Razer eGPUs. We only use parts from the same brand to test them out today.
Understand the Thunderbolt connection
The way these devices work is quite simple. They all use an Intel Thunderbolt controller that picks up PCIe signals on one end and spits out Thunderbolt on the other end. There's also a USB-C controller in the mix to manage the connection. And that's about it. Only two active components and one power supply.
The Razer Core X specifically uses a JHL6540 Thunderbolt 3 controller. This chip supports up to 4 lanes of PCIe Gen 3 traffic, a DisplayPort interface and an additional port that can carry USB 3.1 Gen 2 or DisplayPort. The JHL6540 chip is a bit older as Intel now uses 8000 series controllers that support PCIe Gen 4.
While the Core X's brains are roughly 5 years old, that's not necessarily a bad thing. The chip still supports the full bandwidth of Thunderbolt 3. The Razer Core V2 we tested in 2018 used two previous generation DSL6540 chips that ran at exactly the same speed of 40 Gbps. In fact, essentially every eGPU on the market uses one of these two chips. Intel has some newer generations of controllers, the 7000 series and 8000 series, but they haven't found much adoption yet. They run at the same 40 Gbps.
That 40Gbps figure seems fast, but it quickly reduces as we start digging a little deeper. Thunderbolt 3 has 8 lanes of dedicated DisplayPort bandwidth. This is always reserved whether it is actually used or not. If we subtract that, that leaves us with 32.4 Gbit / s for our PCIe traffic. Since Thunderbolt uses 8b / 10b coding (10 bits are sent over the line for every 8 data bits to make error correction easier), the usable bandwidth is further reduced to 25.92 Gbit / s. This is where the "up to 4 lanes of PCIe gen 3.0 traffic" rating comes into play. Take a look at our PCIe benchmark to see how different generations and slot widths affect GPU performance.
Core X external design
Now that we understand how this box works from the inside, let's take a look at the physical design. From the front it is immediately apparent how big the thing is. It measures 6.6 "x 14.7" x 9 "(168mm x 374mm x 230mm) and weighs just over 14 lbs … without the GPU.
The outer case feels like aluminum, which gives it a sturdy and sturdy feel. The front is made of grooved plastic with a slight gap around the edge. The color scheme I have is the "Mercury" variant, but there is also a black version with a black coating on the metal and black plastic on the front. Either way, it's a very professional look with no RGB and bling that can be found on some other parts of Razer.
If that's more of your style, Razer also has a "Chroma" version of the Core X with RGB lighting and a few extra features. We'll talk about that later.
Both sides have cutouts with mesh for airflow. The mesh on the right has a silver Razer logo in the middle when viewed from the front. The opposite side is plain. On the back we find the pull-out compartment in which the electronics are located. It slides on rails and is secured with a swiveling handle. This has nice leverage and you can really tell when the tray is securely locked into place. Some mechanical engineers had a good time doing it.
You will find that the back is standard with no additional ports or features. You have the power adapter connector, a power switch, the USB-C connector, and then a cutout for the GPU. I found the included Thunderbolt 3 cable to be much worse than expected. It didn't always connect well to the laptop and repositioning it sometimes resulted in the connection being lost.
Inside the Razer Core X.
For this test we have an RTX 3080 from Manli. I was surprised that there aren't at least a couple of extra USB ports here. The Thunderbolt controller inside has a second port that doesn't appear to be in use and that supports USB 3.1 Gen 2. Another option would have been to add a hub to support the additional ports. Granted, this would degrade performance slightly, but the convenience makes it worth it. It would have only been a few dollars in extra parts. The Chroma version has 4 USB ports and an Ethernet port, but costs $ 100 more. It seems like Razer deliberately restricted the Core X to get people on the Chroma version.
OK, enough ranting; back to the product we have here now. Before buying, make sure your GPU will fit. The RTX 3080 included in my test kit was a bit too big and I had to be very careful, otherwise the fans would drag on the sides of the case. It's a 3-slot card, but it's not very common so you probably won't have this problem. The Core X supports cards that are 12.99 "x 6.29" x 2.36 ". That is 330mm long, 160mm high and 60mm deep. I might have made the case 5mm wider if I had I would have designed it to be compatible with even the thickest 3 – slot machines.
Installing a card on the sled is easy. It plugs into the PCIe slot with a single thumbscrew to support it in the back. The fans are positioned directly behind the side cutout to ensure good airflow. On the other side there is an additional fan that cools the back of the card. If you don't have liquid cooling, the Core X will perform better than most desktops in terms of heat and airflow. The GPU fans are located right next to the Core X's network, so they always get fresh air. No CPU or hard drives to heat up. After installing the GPU, two 8-pin power cables are available that can be connected if necessary.
Here are the guts of the Core X with the card removed. Not much is going on here as you can tell from the circuit board. I do appreciate the side release PCIe slot though. There is a seemingly simple DC-DC converter on the right side of the board, the Thunderbolt controller is on the top left of the board, and the USB-C controller is on the bottom left. The rest is just support circuitry and power management.
Next, let's take a look at the included power adapter. It is a 650 W unit, 600 W of which is available on the 12 V rail. The power supply has a 24-pin ATX connector, an 8-pin connector for the power supply of the fan and the PCIe slot as well as two additional 8-pin PCIe cables.
That should be fine for most graphics cards, but just check that your GPU isn't drawing more than 550-600W. If you need extra power, the Core X Chroma has a 700W supply. The high-performance locking mechanism is also visible from above.
Overall, I was very happy with the mechanical design. It's sturdy and feels like a real thought has gone into its construction. Definitely not cheaper plastic like other systems on the market. It's not easy, but these systems are not portable. There is not much else to be said. It's a metal box with a power supply that you plug a GPU into.
Now let's look at some performance metrics. I can see that the Core X and other eGPUs are useful for both games and workstations, so I tested both aspects. It is important to note that the individual results in each test are not as important as they will depend on the GPU you are using.
The figure of merit here is the ratio between the performance of the GPU in a desktop system and in the Core X. If the Core X were 100% efficient and Thunderbolt 3 had infinite bandwidth, you would expect these values to be the same. However, due to the overhead and losses along the way, using the Core X will not give you its full performance.
Remember that due to the limitations of Thunderbolt, we only work at 4xPCIe 3.0 speed. Plus, all eGPUs on the market use the same Intel Thunderbolt controllers, so they run the same speed across the board. If you switch to a different case, you won't get much, if any, performance benefit.
We ran the tests three times: first with the Core X and the laptop's internal screen, then with the Core X and an external 1080p monitor, and finally with the RTX 3080 in a desktop system. There is no resolution limit, but I kept everything at 1080p as that is the resolution of the Book 13 I tested with.
In both games we tested, we see that the Core X's performance is around 20% below that of a normal desktop system. The results will be a little closer for less GPU-intensive games, but these results are in line with previous generations.
It's also interesting that you can expect a 5-10% improvement in performance when using the Core X with an external monitor. This is intuitive as the GPU does not have to send the display data back to the laptop for it to be processed on the integrated screen. All the stuff comes out of the ports of the GPU as usual. The results would be the same even if more games were tested. What interests us here is the performance of the Core X, not the individual GPU.
When I turned to the workstation, I ran the tests the same way I did the games, and the results here are pretty interesting. I used SPECviewperf 13 which has real application traces from some of the most widely used industrial software. We see different levels of performance in every application tested, even those in the same category.
Modeling in Maya on an external monitor offers similar performance to the desktop system, but is massively affected when switching to the internal monitor. 3ds Max has a similar 50% performance hit when compared to the desktop, and using an external monitor doesn't help much at all. Medical applications on the internal screen of the laptop show a performance drop of 30% compared to the desktop system, but only 5% when using an external monitor. Power applications are basically flat, which is a perfect result for the Core X.
The CAD applications tested produce roughly similar results. The drop in performance from an external monitor to the internal screen was much greater than that from desktop performance to an external monitor. Catia on the Core X with an external monitor was 10% slower than on a desktop, Creo was 20% slower, NX was 10% slower and Solidworks was 5% slower.
When you look at all of these tests, it is clear that every application you use has a huge impact on the performance that you can expect. Even if you're not getting the full power, I can see the Core X becoming a popular option in Company Settings. Corporate IT departments like to standardize the equipment they give to employees. This helps reduce overhead as fewer systems to maintain. With an eGPU like the Core X, they can give all employees the same laptop, but still have the option to provide additional GPU power to those who need them.
What we learned
If you take a step back to comment on the overall user experience and test the Core X with the Razer Book 13, there wasn't much to configure. Just make sure you have the Thunderbolt and the correct GPU drivers and you're ready to go.
When you plug in the Core X, a small popup will appear informing you that the GPU is active. It's really plug and play. You can also see which apps are actively running on the GPU. In any case, it's nice to be able to massively increase the graphics performance of your laptop by connecting a single cable. The only usability issue I noticed was a stutter on an external monitor when the laptop screen was closed. Opening the laptop screen seemed to fix this.
The Core X is currently priced at $ 400, which is $ 100 more than it used to be. With the updated Core X Chroma, you get some extra ports, a bit more power, and RGB lighting for $ 500. Either way, it's a heavy price to pay. However, compared to the alternative, it is far cheaper than buying a new desktop if you already have a powerful laptop. The pricing is also high compared to other products on the market. This website is a great place to keep track of eGPU prices if you want a quick reference guide.
One disadvantage of selling a product in this market is that it can be difficult to distinguish your system from others. Since they all use the same chips, there is little or no difference in performance between providers. The build quality of the Core X is great, however. If this is important to you, go for it and you will be happy.
If you'd rather save some cash, SonnetTech's eGPU costs $ 100 less and has a newer Thunderbolt controller. Mantiz's Saturn Pro eGPU is $ 70 cheaper, has a slightly more powerful power supply and additional I / O ports. Granted, the extra I / O ports degrade GPU performance slightly as they take up some bandwidth when used.
On paper there are some other boxes from Gigabyte, Lenovo, and Cooler Master. A GPU is pre-installed in the gigabyte box, so it cannot be updated and availability is currently poor. I would stay away from this one. The Lenovo Legion BoostStation and the Cooler Master EG200 are currently not available for purchase.
In summary, I was happy with the Razer Core X. It does exactly what it is supposed to do without the fluff. You won't get the full performance of the external GPU you use it with, but that's to be expected and there's nothing on the market that could perform better. I wish the Core X had some extra I / O ports, and the case isn't exactly cheap, but if you're in the market for something like that, it's a perfectly viable solution.