What graphics card has the best price-to-performance for use in an eGPU enclosur...
 
Notifications
Clear all

What graphics card has the best price-to-performance for use in an eGPU enclosure considering Thunderbolt 3 overhead and performance limitations?  

  RSS

Results45
(@results45)
Active Member
Joined: 1 month ago
 

Hi all,

I am preparing to put together a portable eGPU gaming & workstation rig for under $1000 in the coming months. Doing a little research, I found out that one of the most significant downsides to using an eGPU are the performance limitations that stem from both PCIe x4 (not x8 or x16 apparently) bandwidth capacity and overhead from Thunderbolt 3/4 itself.

So begs the question: at what point does using a more powerful card like a GTX 1080, RTX 2070, or Radeon VII in an external GPU enclosure not worth the cost due to performance bottlenecks and/or inefficiencies?

Sure, the RTX Titan can saturate four PCIe lanes more effectively than an RX 580 (or so it seems ~ correct me if I'm wrong), but it does not seem like it's worth the price if I'm going to see a 35-45% performance hit in games and certain professional applications when plugged into an Thunderbolt 3 GPU box instead of a tower PC. Not to mention that even using GTX 1070 I will see at least a 5-10% hit in Shadow of the Tomb Raider and up to a 25-30% hit in a few other games and GPU-heavy programs.

If this is truly the case, then I plan stick to the following sub-$200* cards from the used market:

*as prices drop in coming months

 

If not then it would be immensely helpful if one can tell me how to get over 80% performance eGPU utilization from more the powerful cards.

 

P.S. Can I use an Apple Thunderbolt cable with a Window laptop?

This topic was modified 1 month ago

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

.

ReplyQuote
itsage
(@itsage)
Illustrious Member Admin
Joined: 4 years ago
 

@results45, If you can find an RTX 2060 for sub $200, that would be my pick from the list.

 

external graphics card builds
best laptops for external GPU
eGPU enclosure buyer's guide

 
2013 Mac Pro (FP D500 x2) [3rd,12C,E] + RX 5700 XT @ 16Gbps-TB2>TB3 (Mantiz Saturn Pro) + macOS 11 [build link]  


ReplyQuote
Results45
(@results45)
Active Member
Joined: 1 month ago
 

@itsage, Agreed. That or the Vega 56, RX 6500XT, or RTX 3040 ~ whichever is most affordable when it comes time to pull the trigger.

Also found out that Thunderbolt support for PCIe 4.0 in the near future may reduce a large percentage of the performance hit from overhead (apparently caused by data transfer protocol standards as well as intercomponent communication):

 

I'm glad I found some clarity, but curiosities remain:

  1. Is the cost practicality for maximum Thunderbolt 3 & 4 performance limited to mid-range cards?
  2. How soon do you think we'll see either Thunderbolt 5 or an updated USB4 standard with 64-80Gbps of bandwidth and 8-lane PCIe 4.0/5.0 support?
  3. Has anyone ever compared eGPU performance efficiency between a Thunderbolt 3 setup and a DIY setup that involves a direct connection between a PCIe x16 riser to PCIe x4 M.2 slot (either via a PCIe-to-M.2 riser extension cable or a PCIe-U.2-M.2 solution)?

 .

This post was modified 1 month ago

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

.

ReplyQuote
joevt
(@joevt)
Noble Member
Joined: 3 years ago
 
Posted by: @results45

Has anyone ever compared eGPU performance efficiency between a Thunderbolt 3 setup and a DIY setup that involves a direct connection between a PCIe x16 riser to PCIe x4 M.2 slot (either via a PCIe-to-M.2 riser extension cable or a PCIe-U.2-M.2 solution)?

https://egpu.io/forums/thunderbolt-enclosures/a-call-for-measurements-isolating-the-thunderbolt-effect/paged/17/#post-14987

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


Results45 liked
ReplyQuote