• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Quick question about PCIe and Skylake vs. Haswell

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
I'm looking to upgrade soon , and I'm going to the Dark Side (Team Blue). Comparing the 5930K , 5820K , and the 6700K. So , PCIe lanes are where my ignorance blooms. The Haswells are at 40 and 28 PCIe lanes , respectively. I can't find that info on the big Skylake. If I'm running a good graphics card (980?) and a sound card and maybe a PCIe SSD , will lane count matter much? Would 28 be enough and leave room for future PCIe additions? There is a hefty price difference for the 40 lane Haswell and if I don't need the lanes there is no sense in buying them.
 

funsoul

Senior Member
Joined
May 3, 2004
Location
NJ, USA
The 40 pcie lane setups really only matter if you want to run multiple vga cards. For example, a pair of modern cards in sli needs 32 lanes (2x16). Since 3 cards would require 48 lanes, they'd be running at x16, x16, x8. This is also part of the reason why 3x-4x cards in sli/xfire show diminished returns.

If you're not considering more than 1 card, don't bother going for the extra lanes as you won't need them.
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
Even if you decide on 2-3 cards then there is barely any difference between pcie x8 and x16. I mean like 1% in general performance as there are still no cards on the market so strong to use full bandwidth of pcie 3.0 x16. The only cards which could use it are 2 GPU versions of the highest series and even then difference isn't big.

In real if you pick 1-2 cards then there is no difference if you get 6700K or 5820K as both will use 8+8 or 16+8 pcie. When you pick 3 cards then it's better to get board with additional lanes as standard setup will limit pcie to 8+8+4 on most motherboards. Some manufacturers decided to make it 8+8+8 but not all as last slot is often x4. Simply check motherboard manual to be sure.
 
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
OK. I was thinking of a scenario that involves an audio card , TV tuner card , discrete graphics card , PCIe SSD , and potentially another graphics card for SLI down the road. I don't think an audio card needs x16 , or the TV card. I wasn't sure about the SSD , though. In all likelihood it will end up just one SSD and one graphics card , with the potential for another card down the road. Trying to decide if it's better to keep my current rig and use it for HTPC and music server and building a gaming/surfing rig or build one big do everything rig. I'm probably better off adding an audio card to this one and keeping them seperate.
In that case , would the Haswell with 6 cores or the Skylake be the better option? Will games be using more cores effectively over the next few years? Real multi-threaded applications are the only reason I have the Haswell as a contender.
 

Evil-Mobo

Member
Joined
Nov 16, 2015
Location
MD
My opinion based on what you just wrote, for similar price point between a 6700K setup and a 5820K setup go with the 6 core.
 
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
There is a better selection of 1151 boards at lower prices , from a quick perusal of the 'egg. The Haswell would be the pricier option , but the difference between the two probably won't be the deciding factor. I just wasn't sure if the Skylake's speed would negate the extra cores of the Haswell in the real world.
 

knoober

Member
Joined
Mar 18, 2015
I actualy read an article from maximum PC about this very topic. Sorry that I cant find a link to it (I read in the flesh and blood version). IIRC the idea was that skylake would open up the ability to use 2x GPU @ x16 and have a PCIe SSD without taking a hit in performance. Based on an article I half remember and cant find anything in a quick search to back up - you are correct in your concern. Folks around here might know a bit more, but I just wanted to tell you that I have heard your concern addressed before - and skylake was the answer. WIsh I could give you better info
 
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
That's good to hear. Asking the right questions about what's relevant to me can be a steep learning curve.

If DX 12 can take advantage of more cores , the 5820K would seem to get the nod here , all else being equal. But all else isn't equal. Skylake is faster per core , but is it enough faster to equal/beat the 5820K in multi-threaded applications? Since the PCIe question seems to be a non issue , I'm down to how good will X chip be in 5 years ? A crystal ball would be nice. LOL
 
Last edited:

funsoul

Senior Member
Joined
May 3, 2004
Location
NJ, USA
Still sticking with my original thoughts but agree with Woomack that the difference is pretty small (only really relevant if you're into benchmarking).

If you want to know how many lanes you 'need', graphic cards take 16 each. You can look up the add-ins you're thinking of to get a total but, generally, they all take 1 lane except for the m2 which (iirc) takes 4.

As for the haswell-skylake thing...haven't tested it myself yet but you can do some searching at hwbot to compare them. For example, compare the below 5820k and 6700k wprime results. Wprime will eat all the cores/threads that you can throw at it and doesn't care too much about ram so it's a decent indicator of raw cpu horsepower.

http://hwbot.org/submission/2936636_demac_wprime___1024m_core_i7_5820k_1min_34sec_629ms
http://hwbot.org/submission/2961649_punk_sods_wprime___1024m_core_i7_6700k_2min_9sec_58ms

The 6c/8t 5820k beats the cyberboogers out of the 4c/8t 6700k. You can also do some searches for 3D benchmark results using both cpus to get a feel for the difference in that area...similar story (on newer 3D benches) but it very much depends on how many cores/threads your particular apps/games can utilize. Lots cap out at 4cores/4threads (or less) in which case the skylake's win.
 
Last edited:
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
The 6c/8t 5820k beats the cyberboogers out of the 4c/8t 6700k. You can also do some searches for 3D benchmark results using both cpus to get a feel for the difference in that area...similar story but it very much depends on how many cores/threads your particular apps/games can utilize. Lots cap out at 4cores/4threads in which case the skylake's win.

And therein lies the question. Wondering if games will continue to up core usage , making the 5820K the sound choice. My gaming mostly consists of flight simulators , like MS Flight , War Thunder , and World of Warplanes. My daughter wants to get back in to WoW with me , too. I'll try to find out what these games do as far as utilizing cores.
 

DaveB

Senior Member
Joined
Dec 18, 2000
The 6c/8t 5820k beats the cyberboogers out of the 4c/8t 6700k. You can also do some searches for 3D benchmark results using both cpus to get a feel for the difference in that area...similar story (on newer 3D benches) but it very much depends on how many cores/threads your particular apps/games can utilize. Lots cap out at 4cores/4threads (or less) in which case the skylake's win.
Minor correction here: "6c/8t" 5820k should be "6c/12t".

At Microcenter, the i7 5820K is $70 cheaper than the i7 6700K. The cheapest X99 motherboard is only $20 more than the cheapest Z170. so an i7 5820K combo is $50 cheaper than an i7 6700K combo. Going forward, games will be using more cores/threads so IMO X99 is a no brainer.
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
In most games it won't make the difference what you pick as games are for a long time GPU limited, not CPU ( at least if you have 4 cores and any Intel ). The only difference is at really high screen resolution and 2+ high end graphics cards.
Maybe 95% games will run almost as good on 6600K as on 6700K or 5820K. There are single titles which are showing better results on 6 cores+ but there are still not many of them.
Games like wow are really old and can run on anything.

When you move from AMD then really any Intel will show improvements. If you think about playing new games then I would get 6600K and invest in better graphics card.

Personally I downgraded my gaming PC couple of times and I barely see any difference. I had 4930K+2xGTX780, then 4790K+GTX970, 5820K+GTX980 and recently 6600K+GTX960 ...
 
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
I'm looking at a GTX 980 for a graphics card with a high resolution monitor (2k-4k) , or a 390x , so I definitely don't want the CPU to hold it back. Then again , the difference between 70 fps and 72 fps doesn't equate to $100+. The more I look at the cost of current parts for a do-everything computer , the more I'm leaning towards a dedicated gaming rig. 16 GB of fast RAM , a small SSD , a good card and a fast chip that won't be the weak link for a few years. And a mobo I can trust. Maybe a little OC , but nothing a good air cooler or AIO water can't handle.
 
OP
Alaric

Alaric

New Member
Joined
Dec 4, 2011
Location
Satan's Colon, US
One more quick question-Is Skylake really that much better than Haswell-E if both are running the same clock speed? I can see a 4 GHz 6700K being faster than a 3.3 GHz 5820K , but is the difference with both at 4 GHz going to be noticeable anywhere but benching?