Will a GTX 970 be Hampered much by an x8 slot?

[MeMyselfAndPi]

I'm looking to get a new motherboard and graphics card. I was thinking about the ASRock Z97 Extreme 6 since I have so many hard drives to hook up. As I was looking at the specs, I noticed the m.2 port utilizing PCIe 3.0 x4 (Ultra m.2). This would be useful for the SAMSUNG XP941 SDDs, which have speeds over a gigabyte per second. The down side is it uses 4 of the 16 PCIe 3.0 lanes which would knock down the PCIe 3.0 x16 slot down to x8 when in use.

I'm planning on getting ASUS STRIX GTX970 graphics card, and my question is, will it make a noticeable difference operating a GTX 970 GPU in a PCIe 3.0 x8 slot?

 

[chenw]

Short Answer, No

 

[buzznut]

Yes, Intel platforms do lack in PCI express lanes. So I would recommend getting a SATA SSD, even 2 in raid would be better.
I have a PCI express SSD, and while it is fast it has given me more than a few problems with my Z77 motherboard.

But to answer your question, the card running at 8X shouldn't cause any issues. For instance, if you had 2 cards and were forced to run 8x, 8X that typically will not be a limiting factor in games or other workloads.

 

[Darkbreeze]

Long answer, maybe. It really depends on the rest of the system, the demands of the game and how optimized the game code is. This goes into detail.

http://www.pugetsystems.com/labs/articles/Impact-of-PCI-E-Speed-on-Gaming-Performance-518/

 

[holyrage]

no at all maybe 2% less fps? and that's it

 

[Darkbreeze]

If you decide to go with dual cards later and have reduced PCI lanes, THEN you might really see a lack of the performance increase you should have experienced with an SLI configuration. A single card doesn't see that much loss since it can't fully utilize the x16 bandwidth anyhow. This may be changing with newer cards and I haven't seen any actual tests that address it like the pugetsystems test that's over a year old, but with dual cards I'd think there would be a performance hit. Especially since you'd already be at x8 on both of the cards to start with using that particular board.

 

[chenw]

Actually there is a bigger problem, if the M.2 slot is occupied, he might not be able ti use SLI, his second PCI-E lane might be switched to a x4, which is not enough to enable SLI.

EDIT: correction, he won't be able to activate SLI if M.2 is populated, the specs state that if the M.2 is occupied, the first PCI slot drops to X8, and the second drops to X4, which is below SLI requirements

 

[Darkbreeze]

So nomatter what, you're not going to see x16 speeds with M.2 being used and cannot use SLI at any point with it. If you have any plans to ever add a second card, I'd seriously consider a higher end board or a board and CPU with more lanes.

If you don't plan to ever run dual cards, it's likely not a big deal. Gaming performance vs read/write speed.

Nice catch chenw. I didn't even notice it on the board specs.

 

[iron8orn]

well if they made it easy they would have to make every board actually good

 

[chenw]

If the mainstream CPUs came with not 16, but 20 lanes, it would save a lot of headaches.

 

[Darkbreeze]

Well, they pretty much do now. Most every enthusiast platform is utilizing more lanes but I know that doesn't help in this case.

 

[MeMyselfAndPi]

Thanks for the fast replies guys! I'm almost tempted to go for one of the newer 2011 or 2011v3 motherboards to utilize the extra PCIe 3.0 lanes. Not only would that fully utilize the performance of my other components, but leaves me a lot of room for upgrade. While not a priority now, it would be nice to have to option to get a cheap used GTX 970 for SLI in the future. But this setup is already costing far more than I've ever paid in the past, so I just may go with it. But even if the GTX 970 is hampered too much by the x8 slot, I looks like I can put the SAMSUNG XP941 SSD in the PCIe 2.0 M.2 port instead, while still maining 80% of it's maximum performance.

*Sigh* So many decisions...

 

[chenw]

x79 lacks M.2, that is only found on the 97 and X99 chipsets, not to mention that the most recent X79 mobo is R4BE, which was released early this year, AFAIK, most of the x79, if not all, are out of production.

 

[Darkbreeze]

x79 lacks M.2

Ok, unlike your previous posts, this is confusing. To what are you referring with this? I don't see anything in this thread related to x79. ????? Just wondering.

 

[chenw]

x79 lacks M.2

Ok, unlike your previous posts, this is confusing. To what are you referring with this? I don't see anything in this thread related to x79. ????? Just wondering.

He was mentioning that he was tempted to go for either 2011 or 2011v3, 2011 is X79 chipset, which lacks M.2, hence if he is going for X chipsets, his only choice at the moment is going for 2011v3, or X99

 

[Darkbreeze]

Ah. Sorry, didn't catch the inference from 2011. Again, my bad. Just wondered as I was like what the heck is he talking about? Heh.