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On Wed, Oct 14, 2020 at 2:56 PM Grant Edwards <grant.b.edwards@×××××.com> |
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wrote: |
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|
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> On 2020-10-14, antlists <antlists@××××××××××××.uk> wrote: |
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> > On 14/10/2020 19:58, Grant Edwards wrote: |
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> >> On 2020-10-14, antlists <antlists@××××××××××××.uk> wrote: |
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> >> |
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> >>> Does your mobo support NVMe drives? Just be aware my mobo is crap in |
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> >>> that it says it supports two graphics cards, NVMe, etc, but if you |
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> stick |
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> >>> an NVMe in the second graphics card is disabled, or if you use both the |
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> >>> NVMe slots you lose a couple of SATA ports, or whatever. Bit of a PoS |
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> in |
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> >>> that regard. |
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> >> |
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> >> I think that's pretty common. NVMe uses PCI-express channels that are |
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> >> often shared with one of the PCI-express "slots" on the motherboard. |
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> >> As a result you can't use both at the same time. |
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> > |
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> > Is that the sign of a cheap/rubbishy mobo? |
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> |
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> No. AFAICT, it's done even on good, highly rated mid-range desktop |
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> motherboards. [I've never spent much time looking into high-end |
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> server-grade motherboards, so I can't comment on those.] |
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> |
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> It's generally a limitation of the chipsets used. There are only so many |
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PCI Express lanes to go around, so it's impossible to have all of the |
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motherboard featured enabled at full blast at one time. Different |
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motherboards have different solutions as to how they partition the lanes. |
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For example, it's almost universal that if you have a single video card it |
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uses 16 lanes, but if you put a second card in the first card will drop |
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down to using 8 lanes and the other 8 lanes will go to the second video |
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card. |
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-- |
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Manuel A. McLure WW1FA <manuel@××××××.org> <http://www.mclure.org> |
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...for in Ulthar, according to an ancient and significant law, |
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no man may kill a cat. -- H.P. Lovecraft |