PCI-Express 16x (versus) SLI

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Hello all,

I feel like a dud asking this because I've been out of the hard core
hardware scene now for a year focusing on business matters. Well the time
has come for me to get another motherboard replacement and I'm looking at
the GA-8AENXP-D. This board has PCI-e 16x which does in affect double the
AGP bandwidth bus.

But, my question is what is the difference between PCI-e and SLI? Do they
work together on the same motherboard, or are they two seperate types of
connections for video cards?

Brad

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

B. Walker wrote:
> Hello all,
>
> I feel like a dud asking this because I've been out of the hard core
> hardware scene now for a year focusing on business matters. Well the time
> has come for me to get another motherboard replacement and I'm looking at
> the GA-8AENXP-D. This board has PCI-e 16x which does in affect double the
> AGP bandwidth bus.
>
> But, my question is what is the difference between PCI-e and SLI? Do they
> work together on the same motherboard, or are they two seperate types of
> connections for video cards?
>
> Brad

SLI *is* PCI-Express, except that an SLI mobo has (2)16X form factor
video slots in stead of only one. I say 'form factor' because the
second 16X slot is not truly a 16 X/lane slot electrically speaking
however. Actually, it's only a 1X slot under normal use, however, it
is can also become a 'shared' slot with the other 16X slot of an SLI
capable motherboard, where the bandwidth available to one 16X slot is
divided into two, with 8 serial data lanes, or "8X bandwidth" available
to each of the 16X slots.

Currently, video card GPUs don't even take full advantage of the 8X AGP
slot. Although video card GPUs will eventually require additional
bandwidth that exceeds 8X AGP, and which a 16X PCI-Express slot
currently offers, the SLI mobos simply provide an interim measure to use
two 8X video cards to take full advantage of the 16X bandwidth of the
PCI-Express bus.

Basically, one 16X PCI-Express slot 'loans' 8 of the 16 serial bus lanes
to another 16X slot, so two PCI-Express video cards (currently using
GPUs that only require 8X bandwidth) can split/share the bandwidth of a
16X PCI-Express bus between them.


-Rick

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

"B. Walker" <bawalkerREMOVE@THISmodemnet.net> wrote in message
news:4qNde.356$8g.4@news01.roc.ny...
> Hello all,
>
> I feel like a dud asking this because I've been out of the hard core
> hardware scene now for a year focusing on business matters. Well the time
> has come for me to get another motherboard replacement and I'm looking at
> the GA-8AENXP-D. This board has PCI-e 16x which does in affect double the
> AGP bandwidth bus.
>
> But, my question is what is the difference between PCI-e and SLI? Do they
> work together on the same motherboard, or are they two seperate types of
> connections for video cards?
>
> Brad
>

AGP for a start has nothing to do with PCI Express or SLI. AGP technology is
totally different to PCI Express. PCI-E has 16x lanes for the graphics card.
SLI motherboards has two PCI-E 16x connectors...but NOT two 16x lanes.

So an SLI motherboard splits the lanes for each graphics card connector to
8x, so two graphics cards are attached to the motherboard using two slots
with each using 8x lanes each. If you only use one slot you can have it set
to the normal 16x lanes.

While the other slot is then reverted to a normal 1x lane connector.

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Thank you very much for helping to clear that up. I wasn't sure if SLI was
a new technology different from PCI-e or what not. Now based on what I'm
seeing chipset wise, SLI is something that does have to be supported via the
chipset because of both bandwidth lanes for the dual PCI-e slots going to
the chipset, correct?


"Rick M." <dishtv@ptd.net> wrote in message
news:fB6dnabvxr_wK-rfUSdV9g@ptd.net...
> B. Walker wrote:
>> Hello all,
>>
>> I feel like a dud asking this because I've been out of the hard core
>> hardware scene now for a year focusing on business matters. Well the
>> time has come for me to get another motherboard replacement and I'm
>> looking at the GA-8AENXP-D. This board has PCI-e 16x which does in
>> affect double the AGP bandwidth bus.
>>
>> But, my question is what is the difference between PCI-e and SLI? Do
>> they work together on the same motherboard, or are they two seperate
>> types of connections for video cards?
>>
>> Brad
>
> SLI *is* PCI-Express, except that an SLI mobo has (2)16X form factor video
> slots in stead of only one. I say 'form factor' because the second 16X
> slot is not truly a 16 X/lane slot electrically speaking however.
> Actually, it's only a 1X slot under normal use, however, it is can also
> become a 'shared' slot with the other 16X slot of an SLI capable
> motherboard, where the bandwidth available to one 16X slot is divided into
> two, with 8 serial data lanes, or "8X bandwidth" available to each of the
> 16X slots.
>
> Currently, video card GPUs don't even take full advantage of the 8X AGP
> slot. Although video card GPUs will eventually require additional
> bandwidth that exceeds 8X AGP, and which a 16X PCI-Express slot currently
> offers, the SLI mobos simply provide an interim measure to use two 8X
> video cards to take full advantage of the 16X bandwidth of the PCI-Express
> bus.
>
> Basically, one 16X PCI-Express slot 'loans' 8 of the 16 serial bus lanes
> to another 16X slot, so two PCI-Express video cards (currently using GPUs
> that only require 8X bandwidth) can split/share the bandwidth of a 16X
> PCI-Express bus between them.
>
>
> -Rick

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

B. Walker wrote:
> Thank you very much for helping to clear that up. I wasn't sure if SLI was
> a new technology different from PCI-e or what not. Now based on what I'm
> seeing chipset wise, SLI is something that does have to be supported via the
> chipset because of both bandwidth lanes for the dual PCI-e slots going to
> the chipset, correct?
>

Yes, SLI definitely has to be supported in the chipset. Currently, only
NVidia offers SLI that I'm aware of, although VIA and ATI hare said to
be working on something similar for their chipsets.


Personally, I see SLI as more of a marketing gimmick for the gamers more
than anything. As soon as video cards with GPUs requiring greater than
8X bandwidth start arriving, the SLI feature becomes useless, and for
the corporate environment, or other niche markets needing multi-head
display, their needs are generally limited to 2D anyway which will be
well served by the currently available PCI video cards for years to
come. Considering the issues Nvidia SLI mobos are having right now, and
the rather stringent hardware/driver requirements, I don't really see
SLI as being worth it.


-Rick

 

[Guest]

Archived from groups: alt.comp.periphs.mainboard.gigabyte (More info?)

Thanks for really clearing that up. I'm going to stick with the new
giga-byte GA-8AENXP-D motherboard (the -DW isn't on the market yet) as my
new platform to build around for years to come.



"Rick M." <dishtv@ptd.net> wrote in message
news:Np6cnXA1ed8KDuXfUSdV9g@ptd.net...
> B. Walker wrote:
>> Thank you very much for helping to clear that up. I wasn't sure if SLI
>> was a new technology different from PCI-e or what not. Now based on what
>> I'm seeing chipset wise, SLI is something that does have to be supported
>> via the chipset because of both bandwidth lanes for the dual PCI-e slots
>> going to the chipset, correct?
>>
>
> Yes, SLI definitely has to be supported in the chipset. Currently, only
> NVidia offers SLI that I'm aware of, although VIA and ATI hare said to be
> working on something similar for their chipsets.
>
>
> Personally, I see SLI as more of a marketing gimmick for the gamers more
> than anything. As soon as video cards with GPUs requiring greater than
> 8X bandwidth start arriving, the SLI feature becomes useless, and for the
> corporate environment, or other niche markets needing multi-head display,
> their needs are generally limited to 2D anyway which will be well served
> by the currently available PCI video cards for years to come. Considering
> the issues Nvidia SLI mobos are having right now, and the rather stringent
> hardware/driver requirements, I don't really see SLI as being worth it.
>
>
> -Rick