This is the question that many users wants to know: How much performance drop of my Video Card i will have if i put it in the eGPU with Thunderbolt 1, Thunderbolt 2 or Thunderbolt 3? I will give you the answer in this thread!

In all benchmarks we can see that, if we play games with FULL HD 1920 x 1080 Resolution (1080p) on External Display the Thunderbolt Number is not a big deal, BUT if we use the laptop Internal Display - the best Thunderbolt we have, the less performance drop we will get and also if you have better video card you will have more performance drop because - better FPS will make more bandwidth, if you use higher resolution than 1080p on External Display you will have less performance drop because of lower FPS:

THUNDERBOLT # PCIE SPEED EXTERNAL DISPLAY 1080P INTERNAL DISPLAY 1080P Thunderbolt 3 32Gbps-TB3 ~20% performance drop ~20% 1060 | ~ 28% 1070 | ~30% 1080 & 1080Ti Thunderbolt 2 16Gbps-TB2 ~20% performance drop TITAN X ~24% GTX 1060 | ~40% GTX1080 Thunderbolt 1 10Gbps-TB1 ~20% performance drop ~50% performance drop PCI Express 126Gbps-PCIe

Thanks to @itsage we finally have result with the same CPU in the same Desktop PC with attached to the motherboard Thunderbolt 3 port eGPU (AKiTiO Node with GTX 980Ti 6GB Hybrid) and the results shows the same close to ~20% percent performance drop with External Display for Thunderbolt 3 (32Gbps)!

GTX 980Ti 6GB Hybrid in Desktop PC (PCIe slot 126Gbps) GTX 980Ti 6GB Hybrid in eGPU (Thunderbolt 3 32Gbps) External Display - 16% performance drop

So after that test we can confirm that all results we saw so far in this thread are true story even they are with different CPUs and some GPUs are overclocked!

UPDATE: Again thanks to @itsage we have complete benchmarks for 1080p (15% performance drop), 1440p (8% performance drop) and 4k (5% performance drop) with the same CPU in the same Desktop PC with attached to the motherboard Thunderbolt 3 port eGPU (Razer Core with GTX 980Ti 6GB Hybrid)

We have full tests with GTX 1060 6GB in eGPU on all Thunderbolt ports vs. Desktop PC and also a Gaming Laptop:

1. Thundebolt 3 (32 Gbps) vs. PCI Express (126Gbps)

1.1 GTX 1080Ti 11GB in eGPU with Thundebolt 3 (32 Gbps)

Most of the eGPU users wants GTX 1080Ti, thanks to @konceptz we can see that we have -20% performance drop of the GPU on external display, on the Internal Display we have -30% performance drop thanks to @ryokun6 post:

1.2 GTX 1080 8GB in eGPU with Thundebolt 3 (32 Gbps)

Another test with EVGA GTX 1080 Hybrid 8GB with 2016 MacBook Pro 13" (i5-6360U) with eGPU with Thunderbolt3 (32Gbps):

GTX 1080 8GB in Desktop PC (PCIe slot 126Gbps) GTX 1080 8GB in eGPU Thunderbolt 3 (32 Gbps) External Display: -20% performance drop

GTX 1080 8GB in eGPU Thunderbolt 3 (32 Gbps) Internal Display: -30% performance drop

1.3 GTX 1070 8GB in eGPU with Thundebolt 3 (32 Gbps)

Another test with AKiTiO Node eGPU with GTX 1070 8GB with ASUS UX501VW (i7 -6700HQ) – Thunderbolt3 (32Gbps) Test:

GTX 1070GB 8GB in Desktop PC (PCIe slot 126Gbps) GTX 1070GB 8GB in eGPU Thunderbolt 3 (32 Gbps) External Display: -20% performance drop GTX 1070GB 8GB in eGPU Thunderbolt 3 (32 Gbps) Internal Display: -28% performance drop



1.4 GTX 1060 6GB in eGPU with Thundebolt 3 (32 Gbps)

Another test with GTX 1060 6GB eGPU (late-2016 13" MBP + GTX1060@32Gbps-TB3 (AKiTiO Thunder3) ) snow us 21-22% perfromance drop if you using Internal Display and External Display with Thundebolt 3 (32Gbps):

GTX 1060 6GB in Desktop PC (PCIe slot 126Gbps) GTX 1060 6GB in eGPU Thunderbolt 3 (32 Gbps) Internal Display: -22% performance drop GTX 1060 6GB in eGPU Thunderbolt 3 (32 Gbps) External Display: -21% performance drop

So we can see from all benchmarks that with Thunderbolt 3 (32 Gbps) with better Video Card we will get more performance drop, its because again of FPS and bandwidth! Also with GTX 1060 6GB will give us the same 21-22% performance drop thanks to Thunderbolt 3 (32 Gbps) on Internal and External Display!

2. Thundebolt 2 (16 Gbps) vs. PCI Express (126Gbps)

2.1 GTX 1060 6GB in eGPU with Thundebolt 2 (16 Gbps)

After i buy new laptop (15' Macbook Pro Retina late-2013 Iris Pro Only) with Thunderbolt 2 (16Gbps) - the performance drop is great even on Internal Display with Optimus vs. Thunderbolt 1 (my old laptop)

GTX 1060 6GB in Desktop PC (PCIe slot 126Gbps) GTX 1060 6GB in eGPU Thunderbolt 2 (16 Gbps) External Display: -16% performance drop GTX 1060 6GB in eGPU Thunderbolt 2 (16 Gbps) Internal Display: -24% performance drop

2.2 GTX 1080 8GB in eGPU with Thundebolt 2 (16 Gbps)

Another test with 1080 eGPU (2015 15" Dell Precision M7510 + GTX1080@16Gbps-TB3 (AKiTiO Node) ) snow us 43% perfromance drop if you using Internal Display with Thundebolt 2 (16Gbps):

GTX 1080 8GB in Desktop PC (PCIe slot 126Gbps) GTX 1080 8GB in eGPU with Thunderbolt 2 (16Gbps) Internal Display -43% perfromance drop

2.3 GTX TITAN X 12GB in eGPU with Thundebolt 2 (16 Gbps)

Another test with one of the best Video Cards: TITAN X 12GB, Akitio Node and 2015 Macbook Pro 15' - Thunderbolt2 (16Gbps) Test:

TITAN X 12GB in Desktop PC (PCIe slot 126Gbps) TITAN X 12GB in eGPU Thunderbolt 2 (16Gbps) External Display: -20% performance drop

TITAN X 12GB in eGPU Thunderbolt 2 (16Gbps) Internal Display: -42% performance drop

3. Thundebolt 1 (10 Gbps) vs. PCI Express (126Gbps)

3.1 GTX 1060 6GB in eGPU with Thundebolt 1 (10 Gbps)

I tested my eGPU performance drop and put my EVGA 1060 6GB in Desktop PC (PCIe slot 126Gbps) and I get 20% performance drop on External Display and 50% performance drop of Internal Display on my eGPU with Thunderbolt 1 (10Gbps):

GTX 1060 6GB in Desktop PC (PCIe slot 126Gbps) GTX 1060 6GB in eGPU Thunderbolt 1 (10Gbps) External Display: -20% performance drop GTX 1060 6GB in eGPU Thunderbolt 1 (10Gbps) Internal Display: -50% performance drop

3.2 GTX 1070 8GB in eGPU with Thundebolt 1 (10 Gbps)

Another test with GTX 1070 in eGPU with MacBook Pro (Retina, 15-inch, Mid 2012) for Thunderbolt 1 (10Gbps)

GTX 1070 8GB in Desktop PC (PCIe slot 126Gbps) GTX 1070 8GB in eGPU Thunderbolt 1 (10 Gbps) External Display: -22% performance drop

To us eGPU users, the performance loss compared to a desktop is negligible.

With eGPU we have 20-50% performance drop on Internal and External Display and this is great, because with GTX 1060, GTX 1070, GTX 1080 & GTX 1080Ti even with this performance drop - we can play all heavy games with 60FPS:

GTX 1060 6GB - HIGH/ULTRA gaming with 1080p on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3)

gaming with on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3) GTX 1070 8GB - ULTRA gaming with 1080p on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3)

gaming with on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3) GTX 1070 8GB - MID/HIGH gaming with 1440p on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3)

gaming with on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3) GTX 1080 8GB & 1080TI 11GB - HIGH/ULTRA gaming with 1440p on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3)

gaming with on External Display (TB1, TB2, TB3) or Internal Display (TB2, TB3) GTX 1080 8GB & 1080TI 11GB - MID/HIGH gaming with 4k only External Display (TB1, TB2, TB3)

PCI Express provides you a 126Gbps

provides you a Thunderbolt 3 provides you a 32Gbps (x4 3.0)



provides you a Thunderbolt 2 provides you a 16Gbps (x4 2.0)



provides you a Thunderbolt 1 provides you a 10Gbps (x4 2.0, but Thunderbolt 1 channel limited to 10Gbps)

Q: Why There is a performance drop by using Internal Display compared with External Display (Monitor)

A: In case of using Internal Monitor, CPU will send data to the eGPU for graphic processing and then eGPU will send processed data again to the laptop to display it on the Internal Display. In this case Thunderbolt bandwidth will be used in two ways and this will waste bandwidth and cause performance drop compared to using External Monitor. By Using External Display (Monitor) CPU will send data to eGPU for processing and then eGPU will forward processed data directly to the External Display (Monitor)