Z97M OC Formula PCIe 3.0 use
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=612
Printed Date: 07 May 2024 at 1:11am
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Topic: Z97M OC Formula PCIe 3.0 use
Posted By: robman1
Subject: Z97M OC Formula PCIe 3.0 use
Date Posted: 11 Aug 2015 at 10:58am
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I know the Samsung SSD SM951 needs an adapter to go from M.2 to PCIe 3.0 because this motherboard's M.2 port will strangle the 951's data flow(AHCi or NVMe). I have looked at the spec sheet for board but can't deduce whether there are enough PCIe 3.0 channels for the https://pcpartpicker.com/part/powercolor-video-card-axr92852gbd5tdhe" rel="nofollow - PowerColor Radeon R9 285 2GB TurboDuo Video Card and the Samsung SM951(128GB) to be slotted in and to work at thier maximum potentials. Can someone please tell me if I screwed up buying this board and if not, which PCIe 3.0 slots do I put these two components in?
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Replies:
Posted By: Xaltar
Date Posted: 11 Aug 2015 at 1:00pm
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The first 2 PCIE x16 slots on your board are PCIE 3.0 and run at X16 with a single gpu and x8 with SLI gpus, the bottom slot is PCIE 2.0 and runs at x4. If you want to use the SM951 on a PCIE 3.0 you will need to place it in the second slot and it is likely that your GPU will run at x8 but there will not be any performance loss on an R9 285 as it isn't able to saturate the bandwidth of a PCIE 3.0 x8 interface anyway. Personally I would put the SM951 in the bottom slot which is PCIE 2.0 x4, I suspect it should still run at or very close to its full performance and your GPU will have its full 16 lanes still.
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Posted By: parsec
Date Posted: 11 Aug 2015 at 1:09pm
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Basic reality first, all the PCIe 3.0 lanes on a Z97 board, or any other Intel 9, 8, and 7 series chipset board are provided by the processor. Next, all the Intel processors that you can use in a Z97 board, or the others mentioned above, provide 16 PCIe 3.0 lanes. The X99 and X79 platforms provide more PCIe 3.0 lanes. Given the way the PCIe 3.0 lanes are allocated, as soon as you use two cards that use PCIe 3.0 lanes, even if only one lane was used by one of the cards, the video card will get eight PCIe 3.0 lanes. The same is true in your case. If an M.2 slot uses two or four PCIe 3.0 lanes, the video card will be allocated eight PCIe 3.0 lanes. The general consensus and reality of video cards using PCIe 3.0 lanes, is that eight lanes will not limit the performance of any current video card. You R9 285 is not a high end card, so will definitely not be limited by being allocated eight PCIe 3.0 lanes. Your board only has two PCIe 3.0 slots, PCIE1 and PCIE3. Video card should be in PCIE1, the SM951's adapter card in PCIE3. ------------- http://valid.x86.fr/48rujh" rel="nofollow"> 
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Posted By: robman1
Date Posted: 11 Aug 2015 at 1:16pm
| I am using i5-4690K CPU, not OCed yet. Does this affect the number of PCIE 3.0 lanes as you mentioned in the basic reality line of your post? |
Posted By: robman1
Date Posted: 11 Aug 2015 at 1:19pm
| And as an afterthought, I should be getting those 2K read and 1.4K write speeds?(the SM951 will be OS hard drive.) |
Posted By: robman1
Date Posted: 11 Aug 2015 at 1:26pm
| Nevermind, I found it on the Intel ARK page for my CPU. PCIe 3.0 x16 lanes. Thank you both for the effort and info. |
Posted By: parsec
Date Posted: 11 Aug 2015 at 1:33pm
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Over clocking the CPU or not does not change the amount of PCIe 3.0 lanes provided by the CPU. I would not suggest over clocking using the BCLK when using an SM951, they are sensitive to the PCIe buss speed and need it to be very close to 100MHz. The specs of the different capacity SM951s are somewhat different. Capacity Read Write 128GB 2050MBs 600MBs 256GB 2150MBs 1200MBs 512GB 2150MBs 1500MBs http://www.storagereview.com/samsung_sm951_pcie_m2_ssd_review" rel="nofollow - http://www.storagereview.com/samsung_sm951_pcie_m2_ssd_review ------------- http://valid.x86.fr/48rujh" rel="nofollow">
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Posted By: robman1
Date Posted: 11 Aug 2015 at 1:38pm
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I could still OC using multiplier method with no affect to 951? (I was not implying before that OCing increases lanes either lol)
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Posted By: robman1
Date Posted: 11 Aug 2015 at 1:54pm
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I just read that the read/write speed tests were performed on PCIe 3.0 x4 lanes so x8 is obviously more than enough to maximize the SM951- AHCi or NVMe. YAY! bring on the 3D XPoint http://www.tomshardware.com/reviews/samsung-sm951-m.2-pcie-ssd,4045.html |
Posted By: Xaltar
Date Posted: 11 Aug 2015 at 2:53pm
Yes you can still OC via multiplier without any problems.
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robman1 wrote: