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FlyingTexan

macrumors 6502a
Original poster
Jul 13, 2015
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Has anyone ever used an external GPU or do they know of stats out there on how well they work? I'm sporting a 13" rMBP 2015 edition and would like to know how well they work. I might be taking a job in Africa soon where I commute back and forth and was thinking of either forking over for a gaming laptop or getting an enclosure with a GFX 1070 or something. Anyone have any idea?
 
Yup, here's a photo (+specs) of my setup below. 2015 15in + GTX 1070. Although, I have a quad core processor.

http://imgur.com/HtqZ6HP

Stats-wise... I play Black Ops 3 + Elder Scrolls Online @ Max Settings/1440p/60 FPS (V-SYNC capped, no frame drops). GTA V @ Very High Settings (no MSAA, Soft Shadows, High Grass, everything else maxed)/1577p/60 FPS.
 
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I have a quad core i7 too I just think it's lower clocked and not sure if it can be overclocked. I've wondered about that how does it work overall? Just plug and play or do you have to get bootcamp and install Windows too?

While I've got you here can external drives be used pretty successfully? What's the fastest? This might be a good option for me where I can just load up an external drive and run whatever from there
 
Yes, please tell me what type of enclosure that is! I have a 13" 2015-rMBP and want to get an external graphics card because the Iris Pro graphics just are not good enough by a long shot!

:apple:
 
I have a quad core i7 too I just think it's lower clocked and not sure if it can be overclocked. I've wondered about that how does it work overall? Just plug and play or do you have to get bootcamp and install Windows too?

While I've got you here can external drives be used pretty successfully? What's the fastest? This might be a good option for me where I can just load up an external drive and run whatever from there

If you have the i7 model, you have the dual-core 3.1 GHz i7 processor. It turbos up to 3.4 GHz, so you'll probably see a steady 3.0-3.2 GHz turbo while gaming which should be fine (mine boosts to 3.7 GHz but sits comfortably @ 3.5 GHz). These processors are not overclock-able.

How does it work overall? I see no more than roughly 60% CPU usage (avg 30%), no more than 6GB RAM usage (avg 2-4GB, and with my GTX 1070, no more than 6GB VRAM usage (avg 2GB).

External GPU performance loss - Expect around a 10% performance loss from your GPU since you'll be running it externally (converting it from PCIe 3.0 x16 to PCIe 2.0 x4). i.e. GTX 1070 6.5 TFLOPs = ~6 TFLOPS externally.

Expect an even larger loss if you won't be using an external monitor.

How to set up (software) - Install Windows 10 (free). Plug in eGPU. Install AMD/NVIDIA drivers. Reboot. Plug n' play from there.

New GTX 1060/1070/1080 and RX 460/470/480 GPU drivers are not out on macOS yet - although, older GPUs are a 1-click install + plug n' play. I don't recommend gaming on macOS. Titles are scarce and OpenGL sucks compared to Microsoft's DirectX.

How to set up (hardware) - The Thunder 2 (see 'Enclosure' below) is a box. I cut off the right wall with a dremel (you can take a mallet and bend it flat) so my ZOTAC GPU would fit. Also, you're going to have to use + re-wire a PC power supply to power the GPU and Thunder 2. Reference this link for guides.

External drives - Install Windows 10 on your MacBook Pro's M.2 SSD. You can install games on an external SSD via USB 3.0. I'd recommend a Samsung T3 Portable SSD ($100+).

Also can you tell me what kind of enclosure that is and if it's loud?

Enclosure - AKiTiO Thunder 2 PCIe Box ($220)

Power supply - EVGA 500B Bronze Power Supply ($45)

GPU to fit AKiTiO Thunder 2 w/o modification - GIGABYTE GeForce® GTX 1070 Mini ITX OC (~$400)

Is it loud? - No. GPU is dead silent under full load with fans @ 50% (remember, I have a HUGE ZOTAC card). MacBook Pro is silent as well for Black Ops 3. For CPU-intensive games (ESO, GTA V), MacBook Pro fans can get loud.

-

If you guys would like to see photos of the build process, I can upload some. If you've got more questions, fire away and when I've got some free time I'd be happy to help - this a very hands-on project unfortunately.

Edit 1: With all of that being said and reading first post again, it may seem tempting to just get a Razor Blade gaming laptop... I'll tell you this. Windows 10 is a nice improvement, but I still f*cking hate Windows. Bugs, glitches, poor UI, forced buggy updates... BLEH. So, that's my attitude of replacing my MacBook just for gaming (not worth it).
 
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Thanks for the info and you're right I only have 2 core I totally messed that up. Secondly, why worse performance if I game on the laptops screen? If I have to do external if just but a gaming laptop. I've also wondered that since it's just the 13" if the cheaper rx480 would do the job. Again thank you for the info!
 
Thanks for the info and you're right I only have 2 core I totally messed that up. Secondly, why worse performance if I game on the laptops screen? If I have to do external if just but a gaming laptop. I've also wondered that since it's just the 13" if the cheaper rx480 would do the job. Again thank you for the info!

Short Answer - Because the GPU has to send frame data back to your MacBook Pro's internal screen via the same connection (i.e. Thunderbolt 2).

Long Answer - Your CPU (MacBook Pro) connects to your eGPU via Thunderbolt 2. It uses bandwidth to send compute data to the GPU. Normally, with an external display, your GPU then sends frame data to the display via HDMI/DisplayPort/etc. leaving the Thunderbolt 2 connection strictly for GPU compute data only. If you tell the GPU to send frame data BACK to your MacBook Pro, it's going to have to use Thunderbolt 2's bandwidth, thus decreasing how much compute data the GPU can receive.

I wouldn't recommend an RX480 - Get an NVIDIA GTX 1060. $10 more, better performance and more frequent gaming-oriented driver updates. For 1080p gaming, the 1060 will pretty much run any game @ max graphics/60 FPS and would pair up nicely with your dual-core i7 CPU.

Final price of eGPU setup (with 1060) would only be ~$525 which isn't bad at all.

- Nice. Do you use some sort of third party internal SSD in your machine? I ask because of your references to an "M.2" SSD, which isn't what comes with the rMBP.

Nope. Stock SSD. Apple advertises our SSDs as "PCIe-based Flash Storage" but what they actually boil down to is this product right here from Samsung.
 
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- Alright. Apple uses a custom PCIe form factor, which is not M.2. Vendors vary between at least Samsung, SanDisk, and Toshiba.

You're right, they do use their own interface. I forgot about that.

I think when I made that graphic I was trying to be very generic and concise, thus "summarizing" Apple's custom PCIe form factor.

SSD speed is what I was trying communicate. Apple's and M.2's being relatively the same (stupidly fast 1.6+ GB/s).
 
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