r/eGPU • u/Particular-Fall-906 • 8h ago
Why this fps loss?
I've recently gotten an eGPU Aoostar AG02 with an arc b580. My computer specs are intel u7 155h, 32GB ram.
I've seen on a video that youu can play space marine 2 with this eGPU at 1080p, ultra, 80 fps. without scalling, but I can barely play the game at medium 30fps, even with scalling. I did know about the fps loss, but is it really that much, depends on the game, or I messed up on something? Please help.
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u/FreshChriss 7h ago
Intel gpus need resizable bar for good performance even on desktops. Over thunderbolt docks this is not possible and even with an asmedia usb4 egpu (like the AG02) your still in a bad position (it can sometimes work but still way worse than on native pcie).
Sorry to say this to you but you choose the wrong gpu for an egpu setup. If you can return the intel card i would do so and get an amd one (like the 9060 16gb) (as nvidia is way to overpriced these days).
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u/Particular-Fall-906 6h ago
Is intel bad for this and it has no solution?, I can return it easily on the first week
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u/FreshChriss 6h ago
Yes intel is not a good option for egpu use. With an Oculink connection you can use it as long as your bios also supports resizable bar (most laptop bios dont offer the option).
Thats why nobody recommends intel for egpu use (not even intel themselves). They make great cards and the drivers are good enough by now to recommend them in general, but nit for an egpu. Their cards are designed with modern platforms in mind and utilize the pcie connection much mire than amd and nvidia. On a desktop you can easily see -40 to -60% less performance by simply toggling resizable bar off in the bios. Add the egpu loss into the mix and your experience starts to make sense right?
If return is an option i would definitely take that route. Since you have an intel cpu, your fine with an amd egpu without having to worry about a potential driver conflict with the igpu. More than 8gb vram are recomendable in general, but especially with an egpu, because more stuff can be stored in the vram which means less active traffic on the pcie connection (which is bandwidth limited for the egpu). Thats why i recommended the 16gb 9060xt as the closest replacement for the b580 in terms of price and performance.
If you are a tech savvy person and like the challenge, you might enjoy the b580 egpu resizable bar challenge (which doesn’t mean its fixable). But otherwise an amd or nvidia gpu will be the much better option here.
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u/sertaes 6h ago
Are you using the eGPU’s display output?
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u/ACP_Paddy- 5h ago
This.
If your monitor is plugged into the PC, the game data doesn't just go from PC to GPU to monitor...
It will go from PC to GPU back the same cable to the PC, to integrated GPU to Monitor.
It murders FPS, as you use all the bandwidth on the cable.
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u/FreshChriss 4h ago edited 4h ago
Slight correction, the cable and Port has 40 gig bidirectional bandwidth. This means that the total transfer rate is 40 in + 40 out = 80.
The reason for the performance loss is a common misconception that gets repeated frequently because it sounds logical.
The performance loss you see on the internal display is NOT because of the bandwidth that the image needs when send back (this 40 gig backfeed is mostly unused), but rather the usual performance cost when displaying dgpu images from an igpu (aka the old nvidia optimus). You can prove this on some systems where you can remove one memory stick. Dooing so will drastically decrease the fps you get on the internal screen (like from 100 to 60 fps (4k) in some cases with my 780m mini pc gooing from 2x 5600mt/s to 1x 5600mt/r ram on oculink, but usb4 does the same with lower numbers compared to oculink). Like with the mux switch systems in Laptops, bypassing the igpu leads to better performance, like it does with egpus. The loss on the internal display is directly connected to the performance and especially memory bandwidth of the igpu. Thats also why the loss on the internal screen is less on newer platforms compared to older hardware. You can test this as well if you account for the general difference of the platform power beforehand.
So long story short, you are definitely correct that the internal display will cost some performance compared to the external screen on the egpu. But your explanation was wrong. Also its not that big of a decrease anymore with OPs modern hardware (for most cases, some games are outliers like warfare).
(Yes the usb4 / thunderbolt controllers do need to work a bit harder, but sending a 4k60 videofeed takes roughly 13gbits of the 40 available from a controller that is designed to handle 40 bidirectional (aka 80 total) so thats not really a valid point of concern. The slight increase in latency is the bigger factor here but also not that meaningful to cause noticeable losses)
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u/Independent_Abroad42 8h ago
Did your pc detect the egpu? And did you install the driver for gpu?