PCIe slots - Questions

Don't see a specific place for your hardware question? This is the forum for you!

Moderators: mac_h8r1, Nemesis

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 9:31 am

UberGerbil wrote:
churin wrote:UberGerbil's statement as quoted is about the motherboard circuit design around the PCIe slot. I had difficulty understanding exactly what he meant and thought end users need not be concerned about.
I took a close look at the mainboard and now understand exactly what his statement means.
I didn't write that -- EJ257 did, and then a nested quote tag got mangled so that it got mis-attributed
My appology and thank you for correcting my mis-quote.
UberGerbil wrote: . . an x1 (or x4 or x8) card has exactly as much power available to it as an x16 card. . . .
If I paraphrase the above based on my interpretation which does not seems correct is the following: The power available from the slot satisfies requirements of any PCIe card. Appreciate your clarification.
churin
Gerbil XP
 
Posts: 435
Joined: Wed Nov 28, 2007 4:38 pm
Location: Atlanta/U.S.A.

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 1:00 pm

churin wrote:
UberGerbil wrote: . . an x1 (or x4 or x8) card has exactly as much power available to it as an x16 card. . . .
If I paraphrase the above based on my interpretation which does not seems correct is the following: The power available from the slot satisfies requirements of any PCIe card. Appreciate your clarification.
That statement is correct. It doesn't matter what the width is the power available is the same. The thing is that video cards require more power than is available so they have extra power connectors direct on the card.
notfred
Grand Gerbil Poohbah
 
Posts: 3736
Joined: Tue Aug 10, 2004 10:10 am
Location: Ottawa, Canada

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 3:27 pm

Exactly. This becomes clear if you look at the actual pin-outs for each of the slot width variants: note (1) the first 11 pins are exactly the same on all, and (2) those first 11 are where all the power pins live; the larger slots add more data and ground pins, but no additional power.
UberGerbil
Gerbil Khan
 
Posts: 9990
Joined: Thu Jun 19, 2003 3:11 pm

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 4:27 pm

Despite of the replies by netfred and UberGerbile, I am afraid it is still not clear for me. Maybe my question was not worded appropriately.
Anyway, I am aware that if a PCIe card comes with a power connector on it, it must be used to power the card instead of relying on the power from the slot. The UberGerbile's statement I quoted previously may have something to do with this.
churin
Gerbil XP
 
Posts: 435
Joined: Wed Nov 28, 2007 4:38 pm
Location: Atlanta/U.S.A.

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 4:39 pm

I'm not sure what you're still confused about.

To summarize: A PCIe slot is capable of providing the same amount of power regardless of the number of data lanes the slot has. If a card requires more power than a standard PCIe slot can provide, it must have its own separate power connector (like the one on many video cards).
(this space intentionally left blank)
just brew it!
Administrator
Gold subscriber
 
 
Posts: 37739
Joined: Tue Aug 20, 2002 10:51 pm
Location: Somewhere, having a beer

Re: PCIe slots - Questions

Postposted on Fri Feb 22, 2013 5:25 pm

just brew it! wrote:If a card requires more power than a standard PCIe slot can provide, it must have its own separate power connector (like the one on many video cards).
Exactly how much power to draw from the slot and how much to draw from the separate power connector(s), that is up to the design of the board I think. Just so that the PCIe slot can supply 75W (have they increased that with newer versions?).
Image
The Model M is not for the faint of heart. You either like them or hate them.

Gerbils unite! Fold for UnitedGerbilNation, team 2630.
Flying Fox
Gerbil God
 
Posts: 24440
Joined: Mon May 24, 2004 2:19 am

Re: PCIe slots - Questions

Postposted on Sun Feb 24, 2013 8:44 am

I thank everyone very much for helping me learn about PCIe.
churin
Gerbil XP
 
Posts: 435
Joined: Wed Nov 28, 2007 4:38 pm
Location: Atlanta/U.S.A.

Previous

Return to General Hardware

Who is online

Users browsing this forum: No registered users and 3 guests