Will an external GPU work with vive?

[Sub2PewDiePie]

So I'm looking to buy an HTC Vive soon and just tested my computer on Vive. Its specs are generally good except for the graphics card, which is a nvidia gtx 1050. I'm using a gaming laptop (default laptop of this no upgrades) and am wondering if I should get an external GPU with a 1070ti for a good experience. Does anybody know if this will work? This is my first time using VR and I can't find anything anywhere else. Thanks.

[Synthesis]

I'm sure there have been users who have tried that before, but it's not recommended. In your case, it's going to tax your CPU significantly and I'd guess that you'll only get choppy performance at best. External GPUs aren't really for gaming anyways, the value there is in rendering and other such time-intensive operations where latency isn't such an issue.

Unfortunately, your base laptop doesn't meet the minimum specs either, so I'd suggest if you want to do VR on a laptop, you may want to update your gaming PC as well. See here for minimum requirements: https://www.vive.com/us/ready/

Thank you!

-John C

[thedevilsjester]

I am curious about your reply to .  In my own research I have read of quite a few people having great results with an eGPU and the Vive or Rift.

 

Reading through some published benchmarks, like this one: https://egpu.io/forums/mac-setup/pcie-slot-dgpu-vs-thunderbolt-3-egpu-internal-display-test/ it seems like, while you do take a performance hit, a decent eGPU on Thunderbolt 3, can more than power VR.  Am I missing something?

 

 

[Synthesis]

 

Thanks for your post. I checked out that link and it doesn't really talk about VR, but they do bring up a good point. You are going to get performance drops on external GPU setups, period. It's unavoidable. 

That's not to say that there aren't users that are willing to factor that overhead in and are still able to do it, it's still not recommended. For 's case, his/her PC isn't really ready for VR as is, so an eGPU approach likely won't work for him regardless.

If you have any examples of users who have successfully set up Vive with an eGPU and are maintaining 90fps at full resolution, I'd be curious to take a look at their specs.

Thank you,

-John C

[HackPerception]

, 

 

Adding on, eGPU setups tend to see ~70% of the performance of the card in real world application. The issue is mostly that the CPU needs to manage all of the bandwidth and routing and thus you'll rapidly become CPU bound. I have experience with the Razer core on a Razer laptop. It works okay but there was a huge difference between a Razer with a I7-7700k and a I7-8600k - the 7700k was crazy CPU bound and the 8600k had higher perf but never crossed 80% utilization. 

[thedevilsjester]

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 wrote:

 

You are going to get performance drops on external GPU setups, period. It's unavoidable. 

 

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Of course, but thats not the question.

 

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 wrote:

For 's case, his/her PC isn't really ready for VR as is, so an eGPU approach likely won't work for him regardless.

Of course, your reply to him was a bit more general though.

 

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 wrote:

and are maintaining 90fps at full resolution, I'd be curious to take a look at their specs.

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I assume by "full resolution" you mean very high/ultra settings with a high super sampling?  I get a pretty solid 90 FPS at 100% resolution with medium to high settings in the games I have played on a chipset thats about half as powerful as a GTX 1080.  Even with up to a 20% performance penality from being an eGPU, that would increase my performance by quite a decent amount.

 

I am not trying to be antagonistic, a GTX 1080 and an eGPU enclosure is not cheap, so I don't want to buy them if its not going to make anything better, so I want honest, real world results.  Have you actually tried this to know that its not a good solution, or are you just guessing?

 

 

 

[thedevilsjester]

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 wrote: 

Adding on, eGPU setups tend to see ~70% of the performance of the card in real world application. 

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Thats not what the various performance benchmarks that I have seen (like the link in a previous post).  There are some results that show 95% of the frame rate sometimes as little as 80% with very few tests dropping below 80%.  So saying up to 70% is a bit misleading.  Do you have any benchmarks to back this up?

 

Also note that 70% of a GTX 1080 is pretty decent for VR, its still more performance than many "VR ready" machines. 

[HackPerception]

, 

 

You're quoting 2D MacOS performance benchmarks - Mac is a tightly controlled hardware environment and Windows based systems have a ton of variability in hardware. You've also linked benchmarks from the era prior to the Specter/Meltdown fiasco - all patched systems fundamentally have significantly lower performance benchmarks (which is why CPU bottlenecking becomes more important). 

 

There really aren't VR specific benchmarks for eGPUs and Vive - that's a niche within a niche. The overall rule of thumb for eGPUs is that you'll see a 15% drop in perf vs a full install on a standard 2D game. That number increases with VR due to how the rendering stack works. On most 7th gen Intel CPU's you'll see a maximum of 70-80% utilization and you'll start to cross into the 80% with 8th and 9th gen processors because you'll be less CPU bound potentially hitting the low 90's depending on your OEM's integrations. 

 

The guts that drive eGPUs are actually almost identical between all manufacturers. Benchmarks are not the most reproducible thing when it comes to eGPUs on Windows hardware due to the vast differences in how OEMs implement TB3 and the overall architecture differences between manufacturers. 

 

I wouldn't focus on numbers as it's pretty system specific, sufficive to say that if you want to use an eGPU enclosure, your CPU is your bounding factor, especially after Spectre/Meltdown. 

[Synthesis]

The bottom line is this: We don't recommend using external GPUs with Vive. Internal testing showed performance drops we found unacceptable across a range of hardware as well as incompatibility issues with some configurations. It was determined that was not a viable option for most consumers.

That's not to say it can't work or it won't work, it's simply that we don't recommend it. We won't stop you if you want to try that, but if it doesn't work, it doesn't work. If it does work, great! Tell us all about it here on the forums.

Thanks!

-John C

[thedevilsjester]

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 wrote:

, 

 

You're quoting 2D MacOS performance benchmarks

The link I put in a previous post is entirely Windows.  Its on Mac hardware, but that doesn't really impact performance any, and if it did, it wouldn't favor the eGPU (which has notoriously terrible bootcamp support).  

 

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 wrote:

On most 7th gen Intel CPU's you'll see a maximum of 70-80% utilization and you'll start to cross into the 80% with 8th and 9th gen processors because you'll be less CPU bound potentially hitting the low 90's depending on your OEM's integrations. 

 Even at the lowest end of your scale 70% of a GTX 1080 is should be way more than enough to run Vive (assuming you have a good CPU), and for those of us that are not going to be heavily CPU bound, 80%-90% is pretty good performance.  I see no reason that a good CPU and a GTX 1080 couldn't hit the Recommended Vive specs (and then some).

 

I don't want to waste the money on an eGPU and a GTX 1080 only to find out they are not going to work well, but nothing you have said convinces me that your statements are anything more than guesswork.  If you have actual documented benchmarks, please share them!  Again it may sound like I am being antagonistic but I am honestly curious about this.