i7 8700k or i7 8650k

[Aklenar]

I am building a computer mostly for training neural nets. Should I get a i7 8650k 6850k (40 lanes) or 8700k (16 lanes) for two 1080 tis. With the latter my 1080 tis will get x16 lanes while the former will allow x8 lanes. Any recommendations? I also want the future option of replacing one of the tis with the monster Titan V. Difference in cost is negligible for me. 

Edited December 11, 2017 by Aklenar
Typo

[Streetguru]

13 minutes ago, Aklenar said:

Threadripper 1900X because 60 lanes?

[Light-Yagami]

will you benefit from 16x16?

[TheGlenlivet]

If you need full 16 lane power for GPUs and money is no issue then the obvious choice is the 40 lane CPU.  Did you mean 6850K?

The x99 platform that a 6850K uses has quite a few boards with dual x16 slots, and some with 4x16.

[just_dave]

Dont get these, get Threadripper 1900X or 1920X on sale

[AlTech]

31 minutes ago, Aklenar said:

I am building a computer mostly for training neural nets. Should I get a i7 8650k (40 lanes) or 8700k (16 lanes) for two 1080 tis. With the latter my 1080 tis will get x16 lanes while the former will allow x8 lanes. Any recommendations? I also want the future option of replacing one of the tis with the monster Titan V. Difference in cost is negligible for me. 

there is currently no such thing as an i7-8650K

[Aklenar]

I'm sorry, I meant 6850k haha. Would 1900x be overkill since I will only need 32 pcie lanes at most?

[Damascus]

22 minutes ago, Aklenar said:

I'm sorry, I meant 6850k haha. Would 1900x be overkill since I will only need 32 pcie lanes at most?

The 1900x has plenty of lanes but its a sluggish chip compared to either i7 once overclocking is involved.

 

Cpu performance, depends greatly on task

Speed related software (gaming, modelung etc.)

 

Short list

1. 8700k
2. 6850k
3. 1900x

Expansive list

1. 8700k
2. 7900x/7820/7800/7920 etc
3. 5960x
4. 6950x/6900k/6850k
5. 1900x/1920x/1950x

Core related software (renders, streaming etc.)  All cpus assumed overclocked.

 

Short

1. 1900x = 8700k
2. 6850k

 

Expanded

1. 7980x
2. 7960x
3. 7940x
4. 1950x
5. 7920x
6. 7900x
7. 6950x
8. 5960x
9. 1920x
10. 7820x
11. 6900k
12. 1900/8700k/7800x/6850k

Pcie performance for your usecase

1. 1900x (Tr4) = 6850k = i9 
2. 8700k 

[Verrm]

The PCIE lanes comes in handy only when there's a ton of information coming in and out of GPU at all times. And I mean a TON. If you take a look at gaming there are games that utilize 100% gpu and 80-100% of CPU power at the same time. To be able to run them this way you'll probably need 4x pcie. At 1x PCIE the power of 1060 geforce gets some bottlenecking. I would think that running your tasks while giving each gpu a 4x or 8x pcie bandwith will be perfectly fine. Afterall this is a ton of bandwith and you probably won't care even if there are milisecond-long stutters here and there - you are not playing games and the performance overall won't be noticeably different.

If you're performing most of your calculations on gpu and the cpu is below 75% utilized you'll probably be fine with x4 lanes for each gpu.

I dont know about neural network workloads and how you perform them but If I were you having my knowledge I'd get the 8700k. Also the 8700k has cores connected in a ring-bus that is a lower-latency connection then in 6850k. Also if your calculations are gpu-bound then there is absolutely no need for 8700k -> the 8700 non-k version is also very powerful and as feature-rich and if you want to play some games - it is performing almost the same in games (1-2% difference).

[Aklenar]

Thanks guys! I'm going to choose the i7 8700k

[ImNotThere]

On 10/12/2017 at 6:20 PM, Aklenar said:

I am building a computer mostly for training neural nets. Should I get a i7 8650k 6850k (40 lanes) or 8700k (16 lanes) for two 1080 tis. With the latter my 1080 tis will get x16 lanes while the former will allow x8 lanes. Any recommendations? I also want the future option of replacing one of the tis with the monster Titan V. Difference in cost is negligible for me. 

might want to check your uses of former and latter

truth be told theres not much if any performance loss from 16x to 8x so as long as you dont need any other pcie cards or pcie storage then go for the 8700k

[Princess Luna]

Just get the i7 8700k with the TITAN V already if you're that badass rich.

 

Taking into account the small chance this isn't trolling the i7 6850k is A LOT slower than an i7 8700k, considering that PCI-e 3.0 8x is enough for the 1080 Ti and going 16x would not increase performance at all you'd only be losing gaming performance.

[Aklenar]

Im curious, why do you think Im trolling?

[Tijhe VV]

If you plan to add 2 or more GPUs, over 64GB RAM and an m.2 Drive, go with the 6850k, as it can max out with 40pcie lanes, 128GB DDR4 Ram, with the only compromise bieng less speed, at factory 3.7GHz, however, with a solid water cooling rig you should easily get it over 4GHz, motherboards are also respectively cheap, at an Asus x99 board being only 200$

[Ebony Falcon]

More importantly than all the above crap

pcie 3 at 8x does not get fully saturated by a 1080ti nor a Titan v so basically what ever you want or is cheeper