cancel
Showing results for 
Search instead for 
Did you mean: 

ROG Xpander PCI-E Lanes + Mobo PCI-E Lanes

rEd2k
Level 7
Ok, I know that many people are as confused about the whole "PCI-E lanes" thing when it comes to the ROG Xpander and the R3E mobo as I am, so if anyone can clear this up for all of us that would be fantastic 😉

ROG Xpander = 64 lanes and the R3E mobo = 36 lanes

Adding on the Xpander (please someone correct me if I'm wrong) DOES NOT increase the amount of available lanes on the R3E mobo.

The Xpander will ONLY give the ability of having 64 lanes available to all cards plugged into the Xpander offering 64 lanes for inter-card-only communication.

So in other words the mobo sees 36 lanes available and ONLY USES THOSE 36 LANES to communicate with the Xpander and the Xpander has 64 lanes avail. for inter-card communication for SLI, and thats it.

This is how I understand it all so far...

So basically the mobo does NOT truly get a "64 PCI-E lanes" upgrade but instead gets an add-on card (ROG Xpander) that is capable of offering 64 lanes for inter-card communication on the Xpander board locally.

Now if anyone knows if the Xpander ACTUALLY DOES somehow increase the lanes available on the mobo DIRECTLY with some magical hardware/bios/software trickery then PLEASE share your info. on this matter. It would be great if the mobo sees TRUE 64 lanes of PCI-E goodness instead of its default of 36 lanes.

I'm sorry if I'm bringin up something that I'm sure has been talked about many times before in different threads, I just want to clear things up regarding the matter of the PCI-E lanes question once and for all as far as the Xpander is concerened. 🙂

Thanks to all for reading my super long post, any help is appreciated 😉
9,297 Views
12 REPLIES 12

martin_metal_88
Level 8
Why don't just you wait for the Xpander to be out before asking all these question? Only few people have played with the Xpander and thefirst review that will be out after the release will probably be ble to answer all your question better than knowledge of some people that haven't used it yet? no?
Martin_metal_88


Colenzo :Coolermaster ATCS 840 | Gigabyte's EP55-UD5 | Intel Core I7 860 @ 3.8Ghz | 4GB G.skill Trident 1600 | MSI GTX460 1GB HAWK Twin frozr | WD 640 black + WD 1TB green + WD 1TB Blue | Pionner DVR-216 | Silverstone Strider Plus 850W | Coolermaster Hyper 212 plus in push pull fan config |

Ask for more!

There's no harm in asking, that's how people learn things.... besides why such a long wait for this product?

The R3E has been on the market for such long time now and all I'm hoping for is some information to make an informed decision if I should buy the Xpander.

Somebody out there must know the answers hence my question(s).

The ROG Xpander just adds two NF200 chips. The NF200 is a bridge that can take 16 PCI-E lanes and duplicate the data to 32 PCI-E lanes. In my opinion Asus should have just integrated the NF200 chips into the R3E itself like EVGA did with the E762 4-Way Classified and Gigabyte with the X58A-UD9, or Asus' own P6T7 WS Revolution board.

True, I definetly agree that ASUS should have just integrated the NF200 chips onto the board to begin with.

On the matter of how many PCI-E lanes available using the ROG Xpander I'm not sure if you answered my question or maybe you didn't understand what exactly I was asking,
as in your post you state that "The NF200 is a bridge that can take 16 PCI-E lanes and duplicate the data to 32 PCI-E lanes."

I already know this fact but it doesn't clarify if the x58 chip on the R3E mobo still limits/BOTTLE NECKS the PCI-E communication (how many lanes avail.) between the 4x SLI and the CPU.

If the Xpander claims it makes 64 lanes available to the system then I want to know if it actually does do it "properly" and some how makes these extra lanes available to the cpu DIRECTLY,
and not through a 36x PCI-E lane bottleneck using the x58 intel chip.

Retired
Not applicable
i coverd this here: http://www.asusrog.com/forums/showthread.php?980-16x-8x-8x-mode-or-an-SLI-Bridge-for-16x-0x-8x-8x-co...
and here
http://www.asusrog.com/forums/showthread.php?773-Xpander-extensive-overview

your if you ran a quad SLI setup on any X58 motherboard, your lanes would be x8 x8 x8 x8 = 32

xpander is the same. it is not x16 x16 x16 x16, it is x8 through all lanes.

and to answer your nf200 question again. you can read my review for a detailed explanation but in short, the R3E was deisgned with 98% of the buyers in mind. only 2 % of the market which is the oc market use 4 way SLI. the other 98% do not. and having 2 NF200 on a board only increases the cost of the motherboard hence evga and gigabyte's board, and when running 1-3 way sli, it actually performs slower and adds no benefit to performance. so this was the smart move on ASUS to not include NF200. faster and more affordable.

for the ocers that want to use 4 way, well now we have the xpander. which combined will still be cheaper than our competitors and if you want a case for gaming use, DangerDen currently offers a case that works with the xpander.

and lastly whats so cool about Xpander is it can be used on the Maximus III Extreme Rampage III Extreme, Rampage III Formula, and the up coming Maximus 4 Extreme. those are TRI SLI boards that can now run quad sli for cheaper. how cool and smart is that...

rEd2k
Level 7
How can this be? "xpander is the same. it is not x16 x16 x16 x16, it is x8 through all lanes."

When ASUS themselves claim "4 x PCIe2.0 x16 slots support up to full x16/x16/x16/x16 configurations" on the ROG Xpander webpage http://www.asus.com/product.aspx?P_ID=KoOXpEACBYpT5R3p&templete=2

So Brian, if what you say is true then I would only get x8 lanes per card in a 4x SLI configuration no matter what, despite what ASUS claims for the ROG Xpander on their website?

Now if you are correct and this is the case then the Xpander is basically nothing more than a 4x SLI COMPATIBILITY CARD ONLY.

This meaning as a consumer I was lead to believe that the Xpander had a possible performance increase by having more lanes available, but in fact is nothing more than just a 4x SLI COMPATIBILITY add-on daughter card ONLY.

That makes me think it's the biggest waste of money to buy one if I stick with my 3x SLI + 1x gtx 460 for sound/physx and by adding the Xpander I would not benefit from any increase in performance unless I REALLY wanted 4x SLI...

So of course the Xpander is REQUIRED by nVidia for 4x SLI to work at all (which is so lame, thanks nVidia...) and even if I bought one I would still only get x8/x8/x8/x8 and not the "ASUS claimed" x16/x16/x16/x16 lanes.

This is really disheartening to say the least because anyone would be led to believe that the Xpander is capable of the x16/x16/x16/x16 claims as I was. ASUS should state on the web page that when in a 4X SLI config the Xpander will only do x8/x8/x8/x8 in reality.

This is all of course assuming that everything is correct stated by Brian 😉 Oh and I had already read those other forums in search of answers earlier but thanks for the links 🙂

After all this discussion though my question STILL stands... Despite the 4x SLI being in x8 on all lanes, I would still like to know if one is NOT using 4x SLI; Does the Xpander have full PCI-E 2.0 x16 lanes usable by the system with NO bottleneck?

From what I gather if Brian is correct stating it will only do x8/x8/x8/x8 while in 4x SLI (which I'm pretty sure he is) then NO MATTER WHAT configuration is plugged into the Xpander ALL CONNECTIONS TO THE CPU in the end only get x8/x8/x8/x8 simply because the x58 chip on the mobo will ONLY allow that configuration with all slots filled on the Xpander with x16 capable cards...

So is ASUS's claims for all four x16 lanes just a marketing gimmick to sell the Xpander? Even if it DOES do what they state then it doesn't matter cuz the x58 chip still only allows 36 lanes.

Please anyone correct me if I'm wrong on any/all this stuff 🙂

I'm still confused, and I MUST APOLOGIZE for that, also sorry about the long post everyone 😉

Retired
Not applicable
You have a very valid concern and I will dig deeper into this to see what's going on.

The xpander was originally designed for over clockers wanting to take advantage of 4 way sli on the r3e. But your usage model does raise a good concern although you can't really see a performance difference between 16x and 8x gen2

I guess the same must be true of the boards that have NF200 chips integrated, so really the only reason for 2x NF200 seems to be an artificial limitation imposed by Nvidia...:rolleyes:

rEd2k
Level 7
Brian your right, there's practically no difference in performance in x16 vs x8 gen2, which is good news for anyone 🙂

The technical aspect about all this really peaks my intrest, but also the fact that I don't want to be mislead by hype on a product I may or may not buy.

I'm not sure if the 2x NF200 chips are really an artificial limitation but instead more of a requirement because of the way SLI is designed. I'm guessing, and ONLY GUESSING, that one chip would be required for the bridge needed for one PCI-E x16 port on the mobo as is the extra chip with the other x16 port creating the "needed" extra PCI-E lanes "required" by nVidia's 4x SLI spec.

But then again, of course nVidia always (like any company) wants to make more money so they impose some stupid chip required for 4-way SLI so that mobo manufacturers are forced to buy the chip and put it on their boards. SO LAME! This decision also makes it more expensive for all of us in the end.

Of course none of this is any new news to everyone.. it's just one of those things that create these big questions on the technical side and always leaves the consumer wondering what to buy and what to do for best performance.. esp if your an enthusiast 😉

Sabishii Hito has a good point in the last post and raises even more questions about the NF200's that are integrated on other motherboards. Are they also limited by what ever PCI-E controller chip that may be onboard? Kinda like the x58 in my case... (if of course that is truly the case, I'm waiting on Brian's info on this atm) I know, I know, one thing at a time, I'm not going speculate further. I just hope that the Xpander will make all my PCI-E bandwidth dreams come true. lol 🙂

A big THANK YOU goes out to everyone for your posts/help on this matter so far, it's very much appreciated 😉