One quick question - which graphics card to buy?
 
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One quick question - which graphics card to buy?  

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Aiden Ilkhani
(@aiden_ilkhani)
New Member
Joined: 11 months ago
 

So I have read a ton of reviews, watched a lot videos on the subject matter of eGPUs and dissected many comparisons and benchmarks. I still have not found the answer to which GPU to purchase. In a PC environment, the rule is quite simple, the better the GPU, the better the performance. Complexity only enters when the factor of value and personal requirements is measured on top.

However, for a GPU in an external enclosure (TB3), is there a peak in performance, by which any greater GPU would only result in diminishing returns of performance?
I am basically asking if it makes sense to buy more expensive cards past a certain point.

I should clarify the laptop that will run this whole show, will be the new Lenovo Yoga C940 15 inch with a 4k internal screen, but I will be running games at 1440p. I am aware that eGPU bandwidth and overhead makes it a better use with external monitor, but that is not an option for me. Furthermore, the laptop has the option of two types of processors, the well-known six core i7 9750H and the 8 core i9 9880H. I have seen eGPU benchmarks with the 9750H, but not the 9880H, so unsure which I will go with as there is a 300USD difference that may not make sense to go for.

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

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

@aiden_ilkhani There's diminishing returns if you're limited by output resolutions and CPU. The higher the resolutions the less performance loss through an eGPU. External monitor is essential in maximizing eGPU performance. Last but not least is the Thunderbolt 3 connection routing and cooling. To date there are only Alienware laptops and 15" MacBook Pros that have Thunderbolt 3 connection routing directly to the CPU. If you get a laptop that routes the TB3 connection through the PCH, make sure this chip has cooling.

 

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]  


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Aiden Ilkhani
(@aiden_ilkhani)
New Member
Joined: 11 months ago
 

@itsage

I see, thank you. I will ask Lenovo if the TB3 routes directly to the CPU or through the PCH.

Would you say that it makes sense to go for the i9 9880 with 8 cores or spend the 300 USD (cost of the option) towards a better GPU?

EDIT: they say it routes through the PCH that has cooling.

This post was modified 11 months ago

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

.

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

@aiden_ilkhani Good to know the Thunderbolt 3 connection is x4 and PCH has cooling. I think $300 buys much more GPU performance gain vs CPU gain.

 

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]  


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Romzy
(@romzy)
New Member
Joined: 11 months ago
 

@aiden_ilkhani

Can you share how you tracked this down? I've been having a bit of a goose chase with Lenovo trying to learn where the TB3 is routed for the 14" model of the C940. One sales rep told me that info isn't available publicly. Another told me that the PCH was not cooled and then referred me to tech support who said TB3 was routed to "both the CPU and PCH" - though they sounded admittedly confused/uncertain about the question. And a final sales rep said that they could confirm that TB3 is routed directly to the CPU. Phew, it's been quite the run around!

@itsage

If TB3 is actually routed to the PCH and it isn't cooled, would this be a major compromise to eGPU performance and/or the laptop's longevity? I appreciate any perspective you'd be able to share!

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

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Aiden Ilkhani
(@aiden_ilkhani)
New Member
Joined: 11 months ago
 

@romzy

There is always the possibility that the representative that I was speaking to, was misinformed, but he took 5-6 minutes to get the information from the "experts" and simply replied that on the 15 inch version, the TB3 routes to PCH which has cooling. If your purchase relies heavily on this being correct, I would advise reaching out to them again and making sure it is the case.

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

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DeauxJoe
(@deauxjoe)
Active Member
Joined: 11 months ago
 
Posted by: @itsage

@aiden_ilkhani There's diminishing returns if you're limited by output resolutions and CPU. The higher the resolutions the less performance loss through an eGPU. External monitor is essential in maximizing eGPU performance. Last but not least is the Thunderbolt 3 connection routing and cooling. To date there are only Alienware laptops and 15" MacBook Pros that have Thunderbolt 3 connection routing directly to the CPU. If you get a laptop that routes the TB3 connection through the PCH, make sure this chip has cooling.

 

I am also trying to get a better understanding of how this works. So if a Laptop has a TB3 routed directly to the CPU then I could stick a 2080 ti in my Core Chroma X and reap the benifits of that GPU on and external 3440x1440 144 monitor? However if the TB3 is routed though the PCH I will experience bandwidth restriction based on the lanes assigned to deal with the GPU in the eGPU? At that point there would be diminishing rates of return? In that case do we know where the limit is? As in how high up the Nivida ladder can I climb before its an issue?

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

.

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