Multiple graphics cards for gaming/mining rig

[mbouchard]

I will be building a Gentoo-based machine for mining, gaming and digital graphics in the near future, and i would like the Gentoo forums' advice regarding graphics cards. I am doing my own research, but there seems to be a lot of old and inaccurate information to sift through.

Basically, this concerns multiple graphics cards. For mining Monero (my primary mining target, but I'll devote some time to whatever is most profitable) I will be running (at least) 2 graphics cards independently, so SLI/CrossFire isn't really relevant there, but for the occasions where i reboot my machine into a gaming profile, I want to get the full effect of my graphics processing power. Some people say that SLI/CrossFire technologies are on their way out or dying; as far as i can tell, they do still work, though i am not sure if they'll work well enough to make it worth it on linux. What are yoiur thoughts on this?

Also, I'm still undecided on what GPUs to get and would appreciate and consider any recommendations you might have. I've pretty much decided on the AMD Ryzen 7 3700x CPU, but I'd love to hear recommendations and other considerations for CPUs as well.

[Banana]

SLI depends on the software. If there is no realy usage of SLI yout do not really benefit from it. It is like more CPU cores. You need the software to use them. I would not make sli a factor for my buing decision.

If you do not care about money, right now AMD as CPU and Nvidia as GPU sounds a good investment

If you plan best for buck, do not go for the latest but still AMD for both.

[steve_v]

Some people say that SLI/CrossFire technologies are on their way out or dying; as far as i can tell, they do still work, though i am not sure if they'll work well enough to make it worth it on linux. What are yoiur thoughts on this?

My thoughts are that SLI/Crossfire is pretty much pointless on GNU/Linux. Unless you play the one game that can take advantage of it, and even then it scales badly and you'd be better off with a more powerful single card for a comparable price.

Long ago when SLI stood for Scan Line Interleaving, support was only required at the driver level and everything just worked. With modern rendering techniques you need support in the application too, as well as a matching driver profile. AFAIK nobody is bothering to do this for GNU/Linux, largely because multi-GPU gaming is dead anyway.

[389292]

SLI/Crossfire are pointless anywhere not just on GNU/Linux, if you want good gaming performance buy a single high end GPU. In professional setting it's different, mulit-gpus are a must, but it doesn't call SLI there, and does not utilize any physical bridge for the cards. It uses software based solutions (CUDA, OpenCL) if you need that, I think nvidia is more widely supported. You should make your own research on specific application that you need support for. 'digital graphics' is limited in GNU/Linux, no GPU will fix that. AMD GPUs are now having better support in Linux - day 1 drivers integrated into the kernel, while nvidia keep peeing in the eyes of their consumers with anti-consumer practices. If you want to support better company buy AMD, they are friendlier toward linux, but they are not always the best performance wise (GPUs). I think Monero's algo is better with AMD GPU, at least it was ~2-3 years ago. I would advise you against mining though, it isn't really worth it on a such small scale, nor does it worth it to buy into crypto right now, don't be "buy high sell low" type of guy.

[mbouchard]

Thank you all for the excellent answers; I'm going to get two AMD cards and I'll just game on one and maybe experiment with running them both in blender, and use them both for mining of course.

I would advise you against mining though, it isn't really worth it on a such small scale, nor does it worth it to buy into crypto right now, don't be "buy high sell low" type of guy.

Quite the opposite, I'm pleased to say. I've cashed out a portion of my stack that I've made huge profits on; with more than enough money, I can afford to mine crypto for largely ideological reasons and build high-end PC. It helps that I live in a cold climate with cheap electricity, but I have other motives than profit.

[Chiitoo]

I'm going to get two AMD cards and I'll just game on one and maybe experiment with running them both in blender

If you're going with Navi (Vega might have issues too), they will most likely not work with Blender (Cycles rendering with OpenCL) [1].

For gaming I've been quite happy with an RX 5700 XT, but at this time, as far as I know, it can not be used for Blendering (issue seems to be there for Windows users as well).

Neither can it be used for FFmpeg h.264 encoding, though it seems like it should be possible when using the proprietary driver.

1. viewtopic-t-1121939.html