Best Intel processor for 1080 sli?

Archonzeus · 30 Jun 2016 at 02:03

Hello. I'm still deciding on a PC build, so far I've picked everything except the CPU.

I hear the Core i7-6700K 4.0GHz (Skylake) Socket LGA1151 Processor - Retail
is one of the better choices but how well will it do compared with others when I SLI some 1080's? (Or crossfire, I dont know the techinical terms)

Budget is £500 at most.

Dave2150 · 30 Jun 2016 at 02:13

For SLI 1080, you'd want a 40 PCI-E V3 lane CPU, such as the 5930k or the 6850k.

Archonzeus · 30 Jun 2016 at 02:20

Ah awesome, Just over my budget then

thanks man! Ill lower the SSD to up the CPU

Dirk Diggler · 30 Jun 2016 at 05:27

Archonzeus said:
Ah awesome, Just over my budget then thanks man! Ill lower the SSD to up the CPU

Remember it's a different architecture, X99 not Z170. So you need a motherboard to suit. You also need to think about which slots the gpus will go in and make sure you maintain the x16 bandwidth, else the upgrade from 6700k could be pointless. I'm assuming you're not watercooling?

Post here for a spec check if you aren't sure.

dreigns · 30 Jun 2016 at 14:55

You wont need a 40 lane cpu if you are doing just two way sli a 28 lane cpu like the 5820k would be more then enough only other reason to have a 40 lane is if you are going to use the new nvme ssd's
The 6700k would be fine in my view it depends on some of the other components

Dirk Diggler · 30 Jun 2016 at 16:47

dreigns said:
You wont need a 40 lane cpu if you are doing just two way sli a 28 lane cpu like the 5820k would be more then enough only other reason to have a 40 lane is if you are going to use the new nvme ssd's
The 6700k would be fine in my view it depends on some of the other components

This is not true, a 40 lane CPU is required for x16 bandwidth on both cards in dual SLI. A 5820k offers nothing over a 6700k for gaming.

~>Dg<~ · 30 Jun 2016 at 17:06

if you editing recording or twitch streaming go the x99 route.

dreigns · 1 Jul 2016 at 11:01

String said:
This is not true, a 40 lane CPU is required for x16 bandwidth on both cards in dual SLI. A 5820k offers nothing over a 6700k for gaming.

I didnt say it did.
There is little performance advantage from x16 x16 to 8x x8 while in sli even in 4k there is a few fps difference in the end its up to each of us to decide if the extra cost is worth it benchmark

Dirk Diggler · 1 Jul 2016 at 11:46

dreigns said:
I didnt say it did.
There is little performance advantage from x16 x16 to 8x x8 while in sli even in 4k there is a few fps difference in the end its up to each of us to decide if the extra cost is worth it benchmark

The difference between x8/x8 and x16/x16 can be 10%.

Why did you suggest a 5820k?

joeyjojo · 1 Jul 2016 at 12:23

String said:
The difference between x8/x8 and x16/x16 can be 10%.

Proof? It's a few percent in all the measurements I've seen.

pandem0nium · 1 Jul 2016 at 12:32

x8 x8 PCIe gen 3 is plenty. The IPC improvement of skylake is probably enough to offset the difference between x16 x16 and is hunderds of pounds cheaper than a 40-lane haswell/broadwell-e.

Dirk Diggler · 1 Jul 2016 at 12:50

joeyjojo said:
Proof? It's a few percent in all the measurements I've seen.

Rather than go by benchmarks, I've conducted my own little experiment
https://forums.overclockers.co.uk/showthread.php?t=18736914&highlight=startername_String

As I say, the difference is up to 10% and it's down to the buyer whether that is worth it. Some may say that the difference may be 5% so why bother, to which I would counter that some games don't have any SLI supoort at all so touché. If we're ploughing an extra £600 in to go SLI on the risk that it doesn't have perfect scaling or any scaling, then why stop there? Why not ensure that the CPU is giving maximum performance where it can? Obviously budgets are important to most, but to some they aren't.

The bottom line is that the best performing chip for a SLI configuration is the 5930k. If the buyer doesn't want to stretch to X99/5930k and if they don't do anything with the PC that will take advantage of the extra 2 cores, then they may as well forget the 5820k and go for a 6700k or maybe even a 6600k depending on budget constraints.

pandem0nium said:
x8 x8 PCIe gen 3 is plenty. The IPC improvement of skylake is probably enough to offset the difference between x16 x16 and is hunderds of pounds cheaper than a 40-lane haswell/broadwell-e.

That's an interesting point. I would like to see 6700k v 5930k SLI benchmark comparisons. I doubt that the IPC improvement in Skylake would equate to equal frames to 5930k in ROTTR with SLI, but I couldn't say for sure that this is actually the case.

joeyjojo · 1 Jul 2016 at 13:22

String said:
Rather than go by benchmarks, I've conducted my own little experiment
https://forums.overclockers.co.uk/showthread.php?t=18736914&highlight=startername_String

Interesting, thanks. I couldn't help put the numbers into a spreadsheet: x16 has a 5.3% ± 4.1% edge (mean pm standard deviation). "Up to 10%" is true but a bit misleading when the average is 5.3%.

If I were you OP I'd price up 6600K/6700K and 5820K/5930k options.

Also it's crucial you tell us what kind of games you're playing and at what screen res. Can't believe nobody else has asked.

Dicehunter · 1 Jul 2016 at 14:16

String said:
This is not true, a 40 lane CPU is required for x16 bandwidth on both cards in dual SLI. A 5820k offers nothing over a 6700k for gaming.

You do not need a 40 lane CPU to have SLI 1080's, And the 16+16 makes zero difference.

8 Pack · 1 Jul 2016 at 14:22

^^^ Correct.

In my testing 8x / 8x Skylake is the weapon of choice for most gaming scenarios including SLI.

imginy · 1 Jul 2016 at 15:26

6700k wins nearly every gaming benchmark and overclocks higher.

Dirk Diggler · 1 Jul 2016 at 15:51

Dicehunter said:
You do not need a 40 lane CPU to have SLI 1080's, And the 16+16 makes zero difference.

I'm not claiming that anyone needs a 40 lane CPU for SLI, I'm saying it's a requirement for x16 /x16. Seriously, zero difference? That's not been my experience.

Rise Of The Tomb Raider shows a 10% uplift with x16/x16 versus x8/x8. If someone wants to clock 2 980ti to 1418 on the core and provide a 2560*1440 benchmark refuting this then fair enough, but like I say I've tested on my own system and the difference is 90 fps v 100fps. Others have benched 90fps with x8/x8 too.

I'm happy to be proved wrong, but it's just now what I've seen through personal experience.

Zero difference? Sorry, I'm not having that without proof.

a66as · 1 Jul 2016 at 18:08

OP whats your overall budget, what resolution and what types of games will you be playing etc.

Supernaut91 · 4 Jul 2016 at 15:26

String said:
I'm not claiming that anyone needs a 40 lane CPU for SLI, I'm saying it's a requirement for x16 /x16. Seriously, zero difference? That's not been my experience.

Rise Of The Tomb Raider shows a 10% uplift with x16/x16 versus x8/x8. If someone wants to clock 2 980ti to 1418 on the core and provide a 2560*1440 benchmark refuting this then fair enough, but like I say I've tested on my own system and the difference is 90 fps v 100fps. Others have benched 90fps with x8/x8 too.

I'm happy to be proved wrong, but it's just now what I've seen through personal experience.

Zero difference? Sorry, I'm not having that without proof.

I'm in agreement with you String, there WILL be a difference, whether it be negligible 1-2fps here and there or ever greater as seen in ROTTR.

robfosters · 10 Jul 2016 at 00:25

What does a 6600k give you in a Z170 board? 8X/8X?