Learn About eGPUs

What is it?

It is an external GPU that is plugged to your computer through Thunderbolt port to increase performance. eGPUs can be the ultimate solution for the people who need the portability of laptops, and the performance of desktops. It comes in 2 configurations:

• Enclosure Only

  It comes with the enclosure and power supply only. They support standard GPU cards, but you have to get your own GPU.

• Enclosure + GPU

  It comes with the GPU built-in. Some might not use standard GPU cards.

How does it work?

eGPUs work by doing the following (over simplified) steps:

1. Receive instructions from CPU
2. Execute instructions (Graphics or Compute)
3. Send graphics to display or store compute results in memory

Look for

• General Benchmarks

  Check out general benchmarks so that you can get a feeling of how the eGPU performs

  One example of such benchmarks is Geekbench

• Specific Benchmarks

  Check the benchmarks that are specific to the game or software that you will be using

  Let's say you only play 1 game, and that is the only thing you do on your computer, then only check how the eGPU performs specifically to the game you intend on playing. If you found a eGPU runs your game to your desired level, then no need to over spend on a faster eGPU.

• Compatibility

  Check Thunderbolt type, power supply wattage, enclosure clearance, display ports and OS

• Your Display Resolution

  Check eGPU performance with your display resolution

  Displays have many different resolutions based on their size, use, and quality. If you have a display with 1080p resolution, and you have a powerful eGPU, your eGPU will not be fully utilized because it is overpowered for 1080p resolution. You need a display with higher resolution to take advantage of your powerful eGPU. The best thing to do is to make sure the eGPU can handle your display.

• Your Display Refresh Rate

  Check eGPU performance can take advantage of your display refresh rate

  Displays have many different refresh rates, most commonly 60Hz. Higher refresh rates are mainly for better gaming experience. If you have a display with 120Hz refresh rate, you need to make sure you get a eGPU that can run your games at your display's native resolution and native refresh rate.

• Power Consumption

  Choose an eGPU with the best performance per Watt for your requirements

  Less power consumption mean less money paid on electricity bill. It also makes cooling the eGPU easier and quieter.

• Noise Level

  Make sure the eGPU has acceptable noise levels

  This is directly correlated with power consumption and cooling headroom. You need less power consumption and more cooling headroom to reduce noise levels.

Avoid

• Future Proofing

  Do not buy an overpowered eGPU for your needs just for future proofing

  Let's say you got the top-of-the-line eGPU X today for $1500, and it performs 20% more than the mid-range eGPU Y that cost today $500. The price of eGPU X is 200% more then eGPU Y, yet only 20% faster. Later next year, the mid-range eGPU Z performs the same as the top-of-the-line eGPU X from last year with newer features yet costing third at $500. This would make your eGPU X depreciate in value considerably. If you were to get the mid-range eGPU every year it would cost much less, and you will have access to newer features. In addition, if you happen to sell your old eGPU for a good price, you will save more. In short, your performance/$ is much less ( diminishing returns ) if you buy top-of-the-line. However, if top-of-the-line is what it takes to cover your needs, then you have no choice but to get it.

• Overclock

  Avoid overclocking your eGPU

  For the most part, overclocking your eGPU will give you negligible results, while increasing power consumption dramatically and could void your warranty.

• Spec Comparisons

  Do not compare eGPUs based on their specs

  Every eGPU is based on an architecture, and every architecture is designed differently. For example, a 1280 Shaders eGPU can be faster than 2048 Shaders eGPU, hence, it is pointless to say that the 2048 Shaders is more than 1280 Shaders, so it must be better. Same thing with cache size, and any other metrics. The best thing to do is check the benchmarks and real world use cases.

• Clock Speeds Comparisons

  Do not compare eGPUs based on their clock speeds

  All modern eGPUs adjust their clock speeds based on usage and power/cooling headroom to save on power and maximize performance. As a result, if you have a fast eGPU clocked at 1.5GHz, but your power/cooling headroom is only enough for it to run sustainably at 1GHz, then it will run at 1GHz, even though it is a 1.5GHz eGPU. Also, a eGPU from architecture X with clock speed of 1GHz can out perform a eGPU from architecture Y running at 1.5GHz. Instead, you should check out how much your eGPU power/cooling headroom is.

• Memory Size Comparisons

  Do not compare eGPUs based on their memory size

  Usually, modern eGPUs come with an appropriate eGPU memory size relative to their performance level. Unfortunately, some manufacturers combine less powerful eGPUs with more memory to deceive consumers with the assumption that more memory means more performance. It is rarely the case where getting more memory will get you more performance. Instead, focus on eGPU benchmarks, not memory size.

• Multi eGPU Gaming

  Do not get more than 1 eGPU for gaming

  Most games do not take advantage of multiple eGPUs. On top of that, the games that do support it do not improve their minimum FPS, which can make the games stutter.

• Bottlenecks

  Make sure there is no bottleneck from your CPU

  Let's say you have the fastest eGPU and a slow CPU, your eGPU will not work at full capacity because it will not receive instructions from the CPU fast enough to keep it busy. Because of that, the eGPU will be mostly idle.

• Thunderbolt Bottleneck

  Make sure your eGPU is not severely bottleneck by your Thunderbolt

  Get an eGPU that is not severely bottleneck by Thunderbolt connection.

• eGPU ports

  Avoid using eGPU expansion ports because they can reduce performance

  Any expansion ports on the eGPU enclosure shares the same bandwidth provided by Thunderbolt with the GPU. Unfortunately, under full load, Thunderbolt cannot provide enough bandwidth for both the GPU and the ports, so the performance will be reduced for both.

• Non-standard eGPUs

  Avoid eGPU enclosures with not standard GPU cards.

  It makes repairs and future upgrades more difficult.