Help! x4 vs x8 lanes for a mid-range AMD Xfire/nVidia SLI setup!

[gam0reily]

Hello,

I am helping my friend in putting together a new system for him, which will enable him to play all the recent dx11 games at 1080p, along with not being too expensive.

I have thought of puttin either a 6870 or a gtx 560 ti, dependent on the cash that is left from his budget. he has planned to get only a single card as of now, and drop in another one later when it's really required.

As of now, we cant find a proper mobo for him, which is also cheap, but at the same time doesn't bottleneck his future expansions (Xfire/SLI).

Coz most of the mobos which he can get in a range of 150$-170$ have x4 pcie 2.0 lanes activated for dual card setups.
From many articles, I have seen an x4 lane setup to bottleneck many cards, in comparison to x8. But also, these cards were 6950s/570s and upwards.
I cudnt find proper benches for cards like 6870/560s that explained the differences between the two.

So, should he increase his budget to get x8-x8 performance? Is it really that good? Or a x16-x4 is fine?

I am assuming this board runs at x16-x4 speed.
http://www.gigabyte.com/products/product-page.aspx?pid=4015#sp

Thx in advance!

 

[AnToN_CheZ]

I have run 6950's on 16X and 4X lanes, and I can tell you that there is not much of a difference to worry about. Sure there will be some performance drop off from running 8X on both, but in general I found that I only lost around 10% on the second card compared to the usage of the first. It's not much to worry about, Crossfire will give you great performance that HOPEFULLY will translate into the games you play most. Sometimes this is not the case, but 16X and 4X setups are not horrible in my experience.

Hope this helps

 

[gam0reily]

I have run 6950's on 16X and 4X lanes, and I can tell you that there is not much of a difference to worry about. Sure there will be some performance drop off from running 8X on both, but in general I found that I only lost around 10% on the second card compared to the usage of the first. It's not much to worry about, Crossfire will give you great performance that HOPEFULLY will translate into the games you play most. Sometimes this is not the case, but 16X and 4X setups are not horrible in my experience.

Hope this helps

thx for ur quicjk reply anton_chez.

Could u take look at the board I mentioned and see if I am right in saying that it runs at x16-x4 mode for dual cards.
Coz now I have gotta feeling that it runs at x4-x4 mode.

 

[Sunius]

Multipost http://www.tomshardware.co.uk/forum/349065-15-mobo-comparison-xfire-setup

And yes, its x16 x4 board.

 

[gam0reily]

Multipost http://www.tomshardware.co.uk/forum/349065-15-mobo-comparison-xfire-setup

yeah, coz, I left out the UD3 in the first post, and then I thought that I should also get some advice as to that too.

 

[aviral]

As we you know that giving more room for keeping things/items is always a better option then in a congested room.Though it will be not a problem but you will need to take precaution while walking thus reducing your performance of movement.

In the same way :-
The same problem will be with the 16x-4x setup when compared to 16x setup or x8-x8.It will be wise to go with x8-x8.As it will give both the gpu's to perform at their maximum level for the price paid by you.Most importantly that every 2-3 months the technology is changing and therefore the standard of GAMING industry too.

In short try to adopt better standard board so that it is future proof.Try to increase the budget regarding the motherboard.

 

[dpp_sunny]

The PCI Express x16 slots, in that motherboard, run at 4x/4x when both the slots are occupied. Moreover the specs say that if any of the PCI Express x1 slots are occupied, the second PCI Express x16 slot operates at x1 as it shares bandwidth with the x1 slots. As anton_chez said, it wouldn't matter if the slots operate at x16 and x4. But x4/x4 configuration will definitely hurt, even for a mid range card. You should be able to find boards with x16/x4 or x8/x8 slots in MSI and Asus.

Cheers!

 

[gam0reily]

That means a gigabyte UD3 should do just fine. thx for the replies.

 

[Sunius]

This one is both cheap and offers x8/x8 speeds:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157271

 

[gam0reily]

This one is both cheap and offers x8/x8 speeds:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157271

@sunius, I cant get an asrock here in my region (asia). So I think either gigabyte or an asus is my only option.

BTW, about this one,

Asus P8Z68V LE-
http://in.asus.com/Motherboards/Intel_Socket_1155/P8Z68V_LE/#specifications

This runs at x16-x4 or x4-x4?