Jump to content
Floatplane payments are migrating! Read more... ×
Search In
  • More options...
Find results that contain...
Find results in...
Sakkura

Skylake & Haswell-E PCIe lane misconception

Recommended Posts

Yet in terms of price, the 5820k is better. We can all agree on this. 


 

Spoiler

Xeon E5 2697 V3, Silverstone TD02, Samsung 64gb 4x16, Asus X99-E WS, PNY Quadro M6000, Intel 750 400gb, 2x Toshiba 4tb, Seagate 8tb, Seasonic 1050xp3, Phanteks Enthoo Pro

Spoiler

i7 5820k, Corsair H110i GTX, 32gb Crucial Ballistix Sport LT, Asus X99 Sabertooth, EVGA Gtx 980ti x2, Intel 750 1.2TB, Seagate Barracuda 4tb, SeaSonic 1050xp3, In Win 805 Black

 

Link to post
Share on other sites

Err z97 has 16 lanes of pcie 3.0 not 8 of 2.0

 

Edit, I see what you did there  :P  :P  :P


CPU: i7 4790k @ 4.4GHz COOLER: Cooler Master Hyper 212 EVO GPU: RX Vega 56 MOBO: MSI Z97s Krait Edition RAM: 16GB DDR3 2400MHz 2x8GB PSU: Cooler Master GM750W STORAGE: 256Gb Samsung SM951 SSD + 250Gb Samsung 840 + 2Tb HGST 7200RPM CASE: AZZA Titan 240X DISPLAYS: Samsung U24E590D 2160p + Acer S220H 1080p OS: Windows 10 Pro x64

Link to post
Share on other sites

Yet in terms of price, the 5820k is better. We can all agree on this. 

I dunno about that, they found in the video that, for a similar system (same RAM, ASUS -A series board for appropriate socket), X99 is more expensive than Z170 by about $100 USD. They trade places in games (game dependent, oddly enough Cities: Skylines performed considerably better on the 6700K). the 5820K only truly won in some synthetic benchmarks.

 

I'd say Z170 wins for the majority of consumers (ok, maybe prosumers)


Aftermarket 980Ti >= Fury X >= Reference 980Ti > Fury > 980 > 390X > 390 >= 970 380X > 380 >= 960 > 950 >= 370 > 750Ti = 360

"The Orange Box" || CPU: i5 4690k || RAM: Kingston Hyper X Fury 16GB || Case: Aerocool DS200 (Orange) || Cooler: Cryorig R1 Ultimate || Storage: Kingston SSDNow V300 240GB + WD Black 1TB || PSU: Corsair RM750 || Mobo: ASUS Z97-A || GPU: EVGA GTX 970 FTW+

"Unnamed Form Factor Switch" || CPU: i7 6700K || RAM: Kingston HyperX Fury 16GB || Case: Phanteks Enthoo Evolv Mini ITX (White) || Cooler: Cryorig R1 Ultimate (Green Cover) || Storage: Samsung 850 Evo 1TB || PSU: XFX XTR 550W || Mobo: ASUS Z170I Pro Gaming || GPU: EVGA GTX 970 FTW+

Link to post
Share on other sites

I dunno about that, they found in the video that, for a similar system (same RAM, ASUS -A series board for appropriate socket), X99 is more expensive than Z170 by about $100 USD. They trade places in games (game dependent, oddly enough Cities: Skylines performed considerably better on the 6700K). the 5820K only truly won in some synthetic benchmarks.

 

I'd say Z170 wins for the majority of consumers (ok, maybe prosumers)

 

In the UK, there's a problem with that.

 

Both CPUs are basically the same price, so you'd be looking at motherboards more than anything, and they can be pricey on the X99 platform.

Really, the motherboard is the only factor that is going to affect how much you dish out for your system. Though, I do still intend to acquire the X99 platform since it calls out to me. Do I need it? Heck no. Do I WANT it? Absolutely!


BLACKSTAR

PROCESSOR - INTEL CORE i7 5820K @ 4.7GHz
MOTHERBOARD - ASUS X99-E WS
RAM - 32GB (4x8GB) CORSAIR VENGEANCE LPX DDR4-2400
CPU COOLING - NOCTUA NH-D14
GRAPHICS CARD - EVGA NVIDIA GEFORCE GTX 980Ti SC+ ACX 2.0 w/ BACKPLATE
BOOT and PROGRAMS - SAMSUNG 850 EVO 500GB
GAMES and FILES - TOSHIBA 2TB
INTERNAL BACKUP - WESTERN DIGITAL GREEN 4TB
POWER SUPPLY - CORSAIR RM850i
CASE - CORSAIR OBSIDIAN 750D

PC PART PICKER LINK

 

Link to post
Share on other sites

yeah the 20 lane limit for skylake is keeping me from getting it. im still thinking about a 5930K as the 40 lanes.... or I wait for broadwell E. I wonder if that will have DMI 3 or a new chipset or will that us X99 still? 

Link to post
Share on other sites
Posted · Original PosterOP

yeah the 20 lane limit for skylake is keeping me from getting it. im still thinking about a 5930K as the 40 lanes.... or I wait for broadwell E. I wonder if that will have DMI 3 or a new chipset or will that us X99 still? 

 

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

 

X99 will almost certainly remain the same for Broadwell-E.

Link to post
Share on other sites

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

X99 will almost certainly remain the same for Broadwell-E.

Bradwell-E may not even exist with how the other non mobile parts have been.
Link to post
Share on other sites

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

 

X99 will almost certainly remain the same for Broadwell-E.

yeah but I want SLI as well. so that just means I wont have enough. especially if pascal can use most of the bandwidth at 16X that means Ill only get 8X each video card. then my PCI e SSD and m.2 my audio card. lots of USB etc..... 

I think for me X99 40 lanes. and wait for skylake - E in 2017 or zen in like 2020 

Link to post
Share on other sites

Just think about it this way. Z170 allows you to one one fast (2000 MB/s+) M.2/U.2/SATAe drive through the chipset without loosing lanes that would be dedicated to the GPU. Basically allowing to to still have SLI and this new storage. The rest of the DMI link just as before is used for all of your I/O internal and external. This also allows companies not to have to necessarily dip into the CPU PCI-E lanes for additional devices like say usb 3.0 or additional NIC's. All this additional bandwidth in the DMI link is not really directly available to the end user unlike X99/X79/X58. With the enthusiast platform you have considerably more PCI-E lanes that you can basically do whatever you want with. Even 28 lanes mean potentially 3 way SLI and a raid card or NIC's. In reality it would probably be 2 way and and additional device like that and at least 2-4 lanes would be grabbed for additional onboard devices like usb 3.1 and NIC's or other devices.

Link to post
Share on other sites

I did not do a great job of breaking that up to make it more reasonable to read, my bad.

Link to post
Share on other sites

Q1 2016 according to roadmap

I don't expect much if it launches, even the Broadway Server chips launched fairly silently.
Link to post
Share on other sites
Posted · Original PosterOP

Just think about it this way. Z170 allows you to one one fast (2000 MB/s+) M.2/U.2/SATAe drive through the chipset without loosing lanes that would be dedicated to the GPU.

 

No, you can run several of them through the chipset without losing lanes for the GPU.

Link to post
Share on other sites

No, you can run several of them through the chipset without losing lanes for the GPU.

You can to some extent but you have to remember all the other I/O including SATA, USB, Audio, etc is all also running through that same DMI connection.

Once the 850 Pro M.2 NVMe is out im sure there will be bench of multiple of them in RAID0 on a Z170 platform. I'm thinking now two will bottleneck, much less more. Closest thing you'd find now is if someone did it with multiple SM951's but up until recently they were so rare it was hard to get a hold of more than one.

Link to post
Share on other sites
Posted · Original PosterOP

You can to some extent but you have to remember all the other I/O including SATA, USB, Audio, etc is all also running through that same DMI connection.

Once the 850 Pro M.2 NVMe is out im sure there will be bench of multiple of them in RAID0 on a Z170 platform. I'm thinking now two will bottleneck, much less more. Closest thing you'd find now is if someone did it with multiple SM951's but up until recently they were so rare it was hard to get a hold of more than one.

 

As I said in the OP, you can't expect to RAID0 for more performance, but other than that it's not really a problem in real-world usage. Where there's rarely any reason to RAID0 SSDs anyway.

Link to post
Share on other sites

Just think about it this way. Z170 allows you to one one fast (2000 MB/s+) M.2/U.2/SATAe drive through the chipset without loosing lanes that would be dedicated to the GPU.

 

http://www.pcper.com/reviews/Storage/Intel-Skylake-Z170-Rapid-Storage-Technology-Tested-PCIe-and-SATA-RAID/PCIe-RAID-Resu

PCPer investigated PCIe RAID performance on Z170 and found that under certain conditions you can get close to the theoretical DMI 3.0 limit of 3500 MB/s.

Link to post
Share on other sites

Did you even read my post? The "20-lane limit" isn't what it's made out to be. The 20 lanes on Z170 is 5 times as much theoretical bandwidth as X99 provides. And the DMI bandwidth is still doubled.

X99 will almost certainly remain the same for Broadwell-E.

20 lanes is only for onboard devices like m.2. Not for gpus.


Intel Xeon E5 1650 v3 @ 3.5GHz 6C:12T / CM212 Evo / Asus X99 Deluxe / 16GB (4x4GB) DDR4 3000 Trident-Z / Samsung 850 Pro 256GB / Intel 335 240GB / WD Red 2 & 3TB / Antec 850w / HD5850 / Win10 Pro x64

HP Envy X360 15: Intel Core i5 8250U @ 1.6GHz 4C:8T / 8GB DDR4 / Intel UHD620 + Nvidia GeForce MX150 4GB / Intel 120GB SSD / Win10 Pro x64

 

HP Envy x360 BP series Intel 8th gen

AMD ThreadRipper 2!

5820K & 6800K 3-way SLI mobo support list

 

Link to post
Share on other sites
Posted · Original PosterOP

20 lanes is only for onboard devices like m.2. Not for gpus.

 

Technically it's possible to run Crossfire off it, it's just a bad idea. Regardless, the 20 lanes on the chipset means those M.2 or other PCIe devices don't have to take lanes that would otherwise be available for graphics cards. In that sense, Skylake + Z170 offers a total of 36 PCIe 3.0 lanes. Just with various restrictions on how those lanes are assigned etc.

Link to post
Share on other sites

yeah but I want SLI as well. so that just means I wont have enough. especially if pascal can use most of the bandwidth at 16X that means Ill only get 8X each video card. then my PCI e SSD and m.2 my audio card. lots of USB etc.....

I think for me X99 40 lanes. and wait for skylake - E in 2017 or zen in like 2020

You literally will have enough. Pascal will use nowhere near the max bandwidth of x16 in gaming and it's doubtful it will even be bottlenecked by gen3 x4. PCIe usage is mainly dependent on the application, not so much the power of the graphics card, and games use relatively low amounts of bandwidth.

The GPUs will run in Gen3 x8/x8 which is more than enough, and any additional devices like M.2 SSDs will run through the chipset without having any effect on the GPUs at all.

Link to post
Share on other sites

http://www.pcper.com/reviews/Storage/Intel-Skylake-Z170-Rapid-Storage-Technology-Tested-PCIe-and-SATA-RAID/PCIe-RAID-Resu

PCPer investigated PCIe RAID performance on Z170 and found that under certain conditions you can get close to the theoretical DMI 3.0 limit of 3500 MB/s.

So you would be capping two SM951's like I thought and RAID0 would be over 4000MB/s read. Your also getting close on write with two as well potentially.
Link to post
Share on other sites

Okay, so watching the 5820K vs 6700K showdown video on Vessel, I came across a common misconception about the PCIe lanes on Skylake and Haswell-E unfortunately being perpetuated by @Slick.

 

The Core i7-6700K, and all the other Skylake CPUs, offers 16 PCIe 3.0 lanes. The chipset offers additional PCIe lanes separately from that. For the Z170 chipset, that's 20 PCIe 3.0 lanes, a huge boost over Z97 which had just 8 PCIe 2.0 lanes. Luke was just saying 20 lanes, which is not really correct; there is a kernel of truth to it though, because while the chipset offers all those lanes, it's still only connected to the CPU by a DMI 3.0 link that's equivalent to 4 lanes of PCIe 3.0 (in addition to the 16 lanes directly from the CPU). Still, you can hook up lots of PCIe 3.0 SSDs to the chipset just fine without affecting lanes for the GPU(s). Just don't expect RAID0 to give you like 10GB/s combined bandwidth.

 

As for the Core i7-5820K, it offers the well-known 28 PCIe 3.0 lanes directly from the CPU. But again, the chipset offers additional PCIe lanes. In this case, X99 is far inferior to Z170, because it only offers 8 PCIe 2.0 lanes (just like Z97).

 

Here are the block diagrams showing what I explained above:

 

IJK4HKh.jpg

 

ONpcDwI.png

 

Do note that the lower-end chipsets, eg. H110, cut down on the PCIe connectivity on offer.

Great post by the way. This really needed addressing as it's an extremely wide misconception. I am going to pin this thread for a while.

Link to post
Share on other sites

Technically it's possible to run Crossfire off it, it's just a bad idea. Regardless, the 20 lanes on the chipset means those M.2 or other PCIe devices don't have to take lanes that would otherwise be available for graphics cards. In that sense, Skylake + Z170 offers a total of 36 PCIe 3.0 lanes. Just with various restrictions on how those lanes are assigned etc.

Even though the Intel Z170 chipset has plenty of lanes for m.2, pcie, and the lanes from the cpu can just go towards the gpus. The X99 cpu itself already has enough lanes to go around, so it doesn't matter if it's shared or not. Z170 chipset may be superior than X99 chipset, but the X99 itself is overall the superior platform.

On X99 you can run SLI at full x16/x16 and still have enough lanes for 2 Intel 750 SSD.*

*except when running on 5820K.


Intel Xeon E5 1650 v3 @ 3.5GHz 6C:12T / CM212 Evo / Asus X99 Deluxe / 16GB (4x4GB) DDR4 3000 Trident-Z / Samsung 850 Pro 256GB / Intel 335 240GB / WD Red 2 & 3TB / Antec 850w / HD5850 / Win10 Pro x64

HP Envy X360 15: Intel Core i5 8250U @ 1.6GHz 4C:8T / 8GB DDR4 / Intel UHD620 + Nvidia GeForce MX150 4GB / Intel 120GB SSD / Win10 Pro x64

 

HP Envy x360 BP series Intel 8th gen

AMD ThreadRipper 2!

5820K & 6800K 3-way SLI mobo support list

 

Link to post
Share on other sites

Yes this was poorly stated in an attempt to shorten the video

 

1) we were only counting PCIe 3.0 equivs

 

2) we narrowed the DMI spec to its linking lanes to the CPU

 

Will be more clear next time, sorry.. this was not the best way for us to do this

Link to post
Share on other sites

Yes this was poorly stated in an attempt to shorten the video

 

1) we were only counting PCIe 3.0 equivs

 

2) we narrowed the DMI spec to its linking lanes to the CPU

 

Will be more clear next time, sorry.. this was not the best way for us to do this

There is no good way because even intel was advertising "20 lanes" which I believe is teh first time since it been a while since the chipset had a real upgrade since sandy bridge. Also it depends per motherboard how many of those lanes from the chipset are going to be available to the user.

Thanks for the reply though.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×