5820k 'only' 28 lanes

[mushtafa]

I keep seeing people recommend the 5930k over the 5820k due to it having more PCI lanes. But just having a Google, the 4790k only has 16.

How does everyone cope with the 4790k with only 16? - Surely everyone copes fine?!

How many lanes does my i7-950 have?

Basically, I want to know how many is minimal, what's the average people use, what's overkill? I know GPUs are 16 lanes each, but that's all I know

 

[Grumbledook]

Really on the whole they've been driven by GPUs. Typically a primary slot runs at x16 but setting it to x8 so you can use those lanes elsewhere (in my case for USB 3) makes very little performance difference.

I'm not 100% sure the following is correct but:

My i5 760 motherboard only has PCIe 2nd Gen lanes, whilst newer boards run with PCIe 3rd gen from the CPU and 2nd gen from chipset. At least that's how I assume it works as to enable USB 3.0 my primary PCIe slot goes to x8.

3rd Gen lanes are really used these days for GPU and the 2nd gen for all the SATA and USB 3 etc. with most people wanting at least 8x on each GPU slot (which is required for nvidia SLI but AMD crossfire can operate with x4 on the non primary cards afaik).

Other devices that use them, tend to be things like capture cards and soundcards and more recently m.2 Ultra drives also need 4x 3rd gen lanes for full speed.

It would appear the x58 chipset for your i7 950 cpu has 40 PCIe 2nd gen lanes with 32 of those for up to dual 16x or quad 8x GPUs. Quite where the other 4 lanes go or what exactly is used for all the SATA USB etc I'm not quite sure and hopefully someone else will enlighten us both...

 

[ALXAndy]

As stated your I7 950 has 40 lanes. However, your I7 950 is X58 and X58 was a high end socket designed for business use first (Xeons and servers etc). X79 also has a lot of lanes, it was only really on the 5820k that Intel cut them. I don't quite know whether they cut them because they were faulty (and thus weren't good enough to be 5930k) or whether they just cut them.

The reason the 4790k does not have issues is because the high end Z97 boards have what is called a PLX chip and this adds more lanes for the system to use, but cheap Z97 boards and lesser boards will only have two X8 lanes for each GPU should you decide to run more than one.

From what I can gather the 5820k is enough for two way SLI.

What you need to know....

What eats the most lanes are GPUs. They can eat up to X16 each. Thus, when you run a 5820k you will only be able to run X16 X8. This only loses around 3-5% from X16 X16 though.

However, start adding lots of X4 devices and you would eventually end up coming up a cropper, because you can not officially run SLI in a X4 slot, or in a higher X slot with only X4 to play with. There used to be a hack to get around it but I think Nvidia finally stopped that.

Crossfire on the other hand? all you officially need is an X4 lane, so you could run tri fire with a 5820k.

I am just about to switch from a 3970x to a 5820k. I will be using all 28 lanes (X4 RAID SSD, two Titan Blacks). I know the 5820k will never match my 3970x 'cause I got a good clocker..

 

[stooeh]

You can run tri SLI with a 5820K as well (x8,x8,x8)

 

[D3K]

I don't quite know whether they cut them because they were faulty (and thus weren't good enough to be 5930k) or whether they just cut them.

Maybe because there's only 300k multi-GPU setups out there? :shrug:

 

[mushtafa]

Thanks for all the info, looks like a 5820k will be sufficient for my needs.

 

[spoffle]

As stated your I7 950 has 40 lanes. However, your I7 950 is X58 and X58 was a high end socket designed for business use first (Xeons and servers etc). X79 also has a lot of lanes, it was only really on the 5820k that Intel cut them. I don't quite know whether they cut them because they were faulty (and thus weren't good enough to be 5930k) or whether they just cut them.

The reason the 4790k does not have issues is because the high end Z97 boards have what is called a PLX chip and this adds more lanes for the system to use, but cheap Z97 boards and lesser boards will only have two X8 lanes for each GPU should you decide to run more than one.

From what I can gather the 5820k is enough for two way SLI.

What you need to know....

What eats the most lanes are GPUs. They can eat up to X16 each. Thus, when you run a 5820k you will only be able to run X16 X8. This only loses around 3-5% from X16 X16 though.

However, start adding lots of X4 devices and you would eventually end up coming up a cropper, because you can not officially run SLI in a X4 slot, or in a higher X slot with only X4 to play with. There used to be a hack to get around it but I think Nvidia finally stopped that.

Crossfire on the other hand? all you officially need is an X4 lane, so you could run tri fire with a 5820k.

I am just about to switch from a 3970x to a 5820k. I will be using all 28 lanes (X4 RAID SSD, two Titan Blacks). I know the 5820k will never match my 3970x 'cause I got a good clocker..

How come you're moving to x99 if you think a 5820 will never match your 3970x?

 

[abui1806]

http://www.techpowerup.com/reviews/NVIDIA/GTX_980_PCI-Express_Scaling/21.html

In my opinion, the 5930K is not a very viable choice given that its price is significant higher than the 5820K. The link above will give you some idea about the graphics performance between PCIe 3.0 16x vs PCIe 3.0 8x. Good luck!

 

[Rroff]

I don't run my GPUs with less than 16 lanes gen 3 each /snob

 

[ALXAndy]

How come you're moving to x99 if you think a 5820 will never match your 3970x?

Because I had a real problem with my rig recently..

Last year I dumped £3500 into a PC (3970x, MSI BBXPII etc). Well the board died about two months ago. The fets were screwed and the CPU even at stock was throttling to 1.1ghz.

So I contacted erm, "another" company and they said they didn't have any so if I wanted a replacement it was a good idea to RMA with MSI.

So I contacted MSI 7 weeks back. Sent the board in.. Waited.. Waited.. Five weeks later they were still ignoring me so I sent a "warm" email to them saying if they didn't contact me back and explain what was going on I would contact action fraud.

They finally emailed me two days later after nearly six weeks only to tell me they don't have any X79 boards at all to replace it with. So I say "OK, can you offer me a GPU?" as by now I had bought a RIVE for £130 (postage on the MSI was £23) and they offered me a GTX 960.

As you can probably guess I was not amused. So, my wife basically bought me one of them new Alienware Area 51s. Obviously we got next business day warranty...

With something like this I need to know it's covered dude. Alienware offer next business day and they mean it too. I had a M11x and had them out four times. Three new keyboards and an entire new motherboard lol. They also keep spares...

So it's a safety thing more than an upgrade.. I don't mind spending £1200 a year for a full onsite warranty. Plus I can either sell the other one or break it into parts and keep spares.

 

[ALXAndy]

Maybe because there's only 300k multi-GPU setups out there? :shrug:

Possibly. Thankfully I only have a X4 SSD and two Titan Blacks so I should be able to run the GPUs X16-X8 and have the lanes left for the SSD. Am cutting back my hard drive count now and finally going for bigger drives.

You can run tri SLI with a 5820K as well (x8,x8,x8)

Doh. LOL true that... I was wondering why Alienware were offering triple SLI configs on the 5820k... How daft of me

 

[Poneros]

The moral of this story isn't to buy Alienware but to hassle MSI & not buy from brands that have ****** CS in the UK.

 

[5960xNvidiaGamer]

I am moving to a 5960k on the 17th of this month from a 2600k. I will only be using 1 card ( 980ti ) but may use more in the future. But even if I was getting a 5820k there would be no issues. For most people 28 lanes is plenty I would think.

 

[ALXAndy]

The moral of this story isn't to buy Alienware but to hassle MSI & not buy from brands that have ****** CS in the UK.

Ah but the underlying problem is that only Gigabyte have a UK based RMA.

So from now on I'm buying pre built complete systems. OCUK do a few that were great tbh.

 

[Troezar]

Sounds like a good reason to buy Gigabyte. For one reason or another I have always bought MSI however the P67 issue took some time to resolve. I certainly consider a different manufacturer next time. I'm amazed they don't hold at least some stock of the higher end boards. It's not practical to keep spares of everything but the lower end owners would be more than happy to accept an upgrade I'm sure in the event of an RMA.

 

[dessimpson]

Sounds like a good reason to buy Gigabyte. For one reason or another I have always bought MSI however the P67 issue took some time to resolve. I certainly consider a different manufacturer next time. I'm amazed they don't hold at least some stock of the higher end boards. It's not practical to keep spares of everything but the lower end owners would be more than happy to accept an upgrade I'm sure in the event of an RMA.

If word of that got out their RMA department would be snowed under!

 

[Troezar]

If word of that got out their RMA department would be snowed under!

Agreed. I have seen this happen though particularly for items no longer in current production. This would have to be an in house policy of course

 

[Boomstick777]

5820K is an absolute monster, it's price compared to Z97 / Haswell options makes it a much better deal as you get 50% more CPU, DDR4 and Quad Channel. If you are running single or dual GPU's those lanes would never be an issue. Performance is phenomenal even at stock. Overclocked it's a beast !