Nvidia GTX980M SLI - PCI-E Lane Utilization

[Ph0en1x-Fl4m3]

Greetings LTT Community,

 

I'm new to the forum so here goes my first post. I recently consolidated all of my PC's (2x desktops) and laptops (4x laptops) into a single beefy laptop that I purchased from Xidax (XM-11 model which is practically a re-branded Sager NP987OU2-G Linus reviewed here: 

 

Specs

• CPU - Intel i7-6700K @ 4.0GHz
• GPU - 2x Nvidia GTX980M SLI
• RAM - G.Skill Ripjaws DDR4 @ 2800 64GB
• SSD Set 1 - 2x Samsung 950 PRO 512GB m.2 in RAID 0
• SSD Set 2 - 2x Samsung 850 EVO 1TB SATA in RAID 1
• OS - Windows 10 PRO
• Screen - 1920x1080 w/ G-Sync @ 75GHz
• WLAN - Killer 1535 802.11ac adapter
• LAN - Dual Killer E2400 10/100/1000 adapters
• 1x USB 3.1 Type C
• 6x USB 3.0
• 1x HDMI 2.0 (Or 1.4, I forget)
• 2x Mini Display

So here is my inquiry, I'm trying to figure out if I wasted money on the m.2 SSD for faster speeds to the OS as they utilize 4x PCI-E lanes each for a total of 8 lanes. The Intel i7-6700K CPU only has 16 lanes per the Intel ARK. So my drives are already utilizing 50% of my lanes. Unknown in the Nvidia website or their own forums can I find information on how many lanes the GTX980M utilizes each much less in SLI mode as I have them currently. Anyone have an idea as to what that answer would be? Am I possibly trying to over utilize the lanes or wasting performance and need to cut back on my m.2 drives? As fast as it is I'm loving the drives but willing to give 1 or both up if need to since the CPU has a limited number of lanes.

[Electronics Wizardy]

THe ssds are running off the chipset, which connects to the cpu over the dmi, not pci. The gpu is connected at 16x. 16x vs 8x won't make a difference.

[CostcoSamples]

I think you better confirm how many extra lanes your chipset has.  Normally the z170 platform only has an extra 4 lanes for pcie drives.  If that is the case, your GPUs are possibly running at 4x each, which could bottleneck a small amount. 

[CostcoSamples]

Ok, found the test results.  Looks like at 1080p, running gtx 980 at pcie 3.0 x4 will result in a 5% fps drop.  

 

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

 

pretty minimal if you ask me.  not sure how the results would change for SLI.  Anyway I don't think you need to worry about it.  

[Cracklingice]

M.2 drives go through the chipset and do not effect the video card.  Confirm with GPUZ if you want.

[Ph0en1x-Fl4m3]

8 hours ago, Cracklingice said:

M.2 drives go through the chipset and do not effect the video card.  Confirm with GPUZ if you want.

Oh hell, that's right. I'm so used to only using aida64, I forgot GPUz existed. Good catch. Although now that I think about it...I bet aida64 would tell me too.

 

*sigh* (Hands in IT card and takes walk of shame)

 

Thanks! ?