X99 Manuals Leak: Core i7-5820K Has Reduced PCIe Lanes?

Subject: General Tech, Processors | August 23, 2014 - 01:38 AM |
Tagged: X99, Intel, Haswell-E

Haswell-E, with its X99 chipset, are expected to launch soon. This will bring a new spread of processors and motherboards to the high-end, enthusiast market. These are the processors that fans of Intel should buy if they have money, want all the RAM, and have a bunch of PCIe expansion cards to install.

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The Intel enthusiast platform typically has 40 PCIe lanes, while the mainstream platform has 16. For Haswell-E, the Core i7-5820K will be the exception. According to Gigabyte's X99 manual, the four, full-sized PCIe slots will have the following possible configurations:

Core i7-5930K
(and above)
First Slot
(PCIe 1)
Second Slot
(PCIe 4)
Third Slot
(PCIe 2)
Fourth Slot
(PCIe 3)
  16x Unused 16x 8x
  8x 8x 16x 8x
Core i7-5820K
First Slot
(PCIe 1)
Second Slot
(PCIe 4)
Third Slot
(PCIe 2)
Fourth Slot
(PCIe 3)
  16x Unused 8x 4x
  8x 8x 8x 4x

If you count the PCIe x1 slots, the table would refer to the first, third, fifth, and seventh slots.

To me, this is not too bad. You are able to use three GPUs with eight-lane bandwidth and stick a four-lane PCIe SSD on the last slot. Considering that each lane is PCIe 3.0, it is similar to having three PCIe 2.0 x16 slots. While two-way and three-way SLI is supported on all CPUs, four-way SLI is only allowed with processors that provide forty lanes of PCIe 3.0.

Gigabyte also provides three PCIe 2.0 x1 slots, which are not handled by the CPU and do not count against its available lanes.

Since I started to write up this news post, Gigabyte seems to have replaced their manual with a single, blank page. Thankfully, I was able to have it cached long enough to finish my thoughts. Some sites claim that the manual failed to mention the 8-8-8 configuration and suggested that configurations of three GPUs were impossible. That is not true; the manual refers to these situations, just not in the most clear of terms.

Haswell-E should launch soon, with most rumors pointing to the end of the month.

August 23, 2014 | 07:41 AM - Posted by Adam C (not verified)

To me, it is a huge disappointment that X99/59xxK is still at max 40 PCIe lanes (5930K and above).

With the onset of 4K (and future higher res as the years go by) it makes sense to have support for 4 x 16x PCIe lanes, and not be forced to use third party hardware on-board.

We buy top end GPUs (780ti and above) yet we are forced to use 8x if we have three or four. Not good enough in my opinion.

The X99 is to be marketed for the high end sector of the gamer/workstation community, so more lanes should have be developed.

August 25, 2014 | 08:10 AM - Posted by ambientblue (not verified)

Except PCIe 3.0 is fine for even the most demanding GPUs running at 8x, even 4x is 95% of the performance. What do you know. Its marketed to enthusiasts and thats why you get more then double the lanes over mainstream platforms, in the 5820k's case its still nearly double the native express lanes and allows 8x/8x/8x with triple GPUs, thats more than enough. BTW a single GTX 880 will easily handle 4K HD anyways.

August 23, 2014 | 10:39 AM - Posted by Anonymous (not verified)

Maybe Nvidia could license the power8 reference design from IBM/Open power, and since Nvidia is already working with IBM to Integrate Nvidia's GPUs as accelerators on a Mezzanine Module, with the Power8, and Nvidia is already a member of the Open Power Foundation, Nvidia could produce a high end gaming server system built around the Licensed power8 reference design, as fast as NVlink is with its CAPI derived coherency fabric, a system like that with 4, or even more, highest end Nvidia cards would not be starved for bandwidth by lack of PCI lanes. That would surely stop Intel from worrying about cannibalizing it server CPU sales by reducing the number of PCI lanes, that and the other functionality that Intel removes for the E chips, maybe even Intel would be forced to make some CPUs with more cores instead of that, never to be utilized for high end gaming, GPU circuitry taking up space on the Die. The Non made for IBM products, Licensed Power8s built from the power8 reference designs, and custom variants, are expected to begin shipping in 2015, and Google will surely be using them, and Nvidia already has a very close technological relationship with IBM, and Open Power. Nvidia most definitely has options in this respect.

August 23, 2014 | 11:32 AM - Posted by PapaDragon

Thanks for the Info Scott!! Well, if two of the rumors hold up about the 5820k , 1. Priced around $350 and 2.its 6 cores/12 threads, then, a few fewer lanes shouldn't be any issue IMO. A small sacrifice.

The lass two generations of 6 core chips being cost prohibitive (sandy-e...Ivy-E) at above $500-$1000, now potentially at $350, thats going to be big for (me)content creators and gamers . The 5820k will no doubt fly off the shelves.

Now..those DDR4 prices..ouch!

August 23, 2014 | 05:41 PM - Posted by Mnemonicman

Not too thrilled that the 5820K has only 28 PCI-E lanes available. This was rumoured for some time now so the blow isn't so bad. Still it is a hex core so at least there is that.

August 23, 2014 | 06:11 PM - Posted by PhoneyVirus

So what I can make from the above chart, is that the Second Slot PCIe would only run at x8, really I though you could purchase any X99 motherboard along with say Intel's Core i7 5820K and still run two graphic cards at full x16. Apparently you can't unless you buy Core i7-5930K, am I reading this right or did something change from the last X79 design.

August 23, 2014 | 06:14 PM - Posted by Scott Michaud

Yeah, you cannot run two GPUs at full x16 unless you have an i7-5930K or up.

August 23, 2014 | 06:20 PM - Posted by PhoneyVirus

@Mnemonicman Wow I'm not to trilled either if your right, only 28 PCI-E lanes available, so I have to give Intel $800 dollars to get the full x16 support to run SLI. Next upgrade will be without a doubt AMD upgrade kit and not have to play Intel's game.

I'm a huge Intel fanboy, but there's a point in time where you draw the line and just get sick of the games they play. Let's hope AMD updates their Chipset in 29 months.

Also didn't know about Quad SLI four-way SLI is only allowed with processors that provide forty lanes of PCIe 3.0.


August 25, 2014 | 08:15 AM - Posted by ambientblue (not verified)

You run 4 gpus at once? perhaps you can afford a 5930k wise guy. You dont need 16x pcie 3.0 to get the full performance from your GPU.

August 28, 2014 | 04:11 PM - Posted by PhoneyVirus

Jealous ant we, no I'm not running Quad-SLI but having such a option would be nice Wise guy. lol


August 23, 2014 | 06:23 PM - Posted by PhoneyVirus

@Scott Michaud Thanks for the info, glad I went with Z97 Chipset and Intel's Core i7 4790K instead of holding off for the X99, just amazing.


August 23, 2014 | 09:08 PM - Posted by Scott Michaud

i7-4790K supports less, only 16 lanes.

August 23, 2014 | 07:36 PM - Posted by QD (not verified)

We should know soon if DDR4 is going to be worth the the extra money soon. As it is- I don't think it is that out of line for the premium. That said, I think they will be charging about double for the 33% difference between 6 and 8 core procs ... something for 1%'ers :p

August 24, 2014 | 09:28 AM - Posted by Anonymous (not verified)

I am waiting until Broadwell to upgrade and I am still rocking out a x58 with a OC'd Xeon Hexacore.

August 25, 2014 | 09:54 AM - Posted by BBMan (not verified)

We might have to wait a little longer?


At least we don't have to deal with the AMD boasts and boon-doggles.

August 25, 2014 | 02:14 PM - Posted by PCPerFan (not verified)

Wow, huge fail. :(

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