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CPU lanes for Dual GPU setup

Posted: Wed Apr 03, 2019 6:56 am
by alecchalmers
Just working out what CPU to spec my new system with.
For GPUs I will be hooking up two 11GB 2080 Ti's
Will they definitely support two GPUs using x16 lanes each?

Overclocked Intel® Core™ i9-7920X 12 Core (2.90GHz @ up to 4.6GHz) - PCIe lanes = 44
Overclocked Intel® Core™ i9-9900X Ten Core (3.50GHz @ up to 4.5GHz) - PCIe lanes = 44

Apologies if this is obvious, just want to make an informed decision.

Re: CPU lanes for Dual GPU setup

Posted: Wed Apr 03, 2019 8:32 am
by glimpse
good day,

x8 per GPU is enough to get all the performance it has to offer for GPU rendering. Also would not advice to go lower as You might have issues with SLI that is needed to enable NVLINK.

8700k/9900k is more than good and actually outperform other, more expensive CPU with more cores, as those would have slower single core clocks.

So choose the part based on Your other needs (simulation and such, how much You would have a need for multicore performance).

Sinc.
tom

Re: CPU lanes for Dual GPU setup

Posted: Wed Apr 03, 2019 3:14 pm
by alecchalmers
Hey Tom,

Thanks for the reply. Just to clarify, if I go with an i9-9900x I still get access to the 44 lanes, which I didn't initially realise.

Now I am contemplating the:
i9-9900x or the i9-9900k

Would the i9-9900x be the best of both worlds in terms of power and lanes, or would you recommend the i9-9900'k' model?
x model has more lanes and cores/threads. The only downside is the Max Turbo Frequency is fewer than the 'k' model by 0.6 GHz.

It seems like not much difference between the 2, with max turbo being the only downside.

Re: CPU lanes for Dual GPU setup

Posted: Wed Apr 03, 2019 4:53 pm
by glimpse
These are two completely different CPUs that also require different platforms (motherboards) to run.

however performance wise they are pretty close. Personally I would stick with less but faster cores than the other way around, as there are plenty of workloads that would benefit from single core performance boost.

Re: CPU lanes for Dual GPU setup

Posted: Wed Apr 03, 2019 8:29 pm
by alecchalmers
I think I'll take your advice and go with the 9900x. Thanks for taking the time to discuss that with me