Talk:PCI Express

Giga bits per second needs fixing

There are mixes of confusing units here I think - GB/s meaning giga bits per second for example.. these need a thorough sweep through. Even Tomshardware had the same figures i think! Bravekermit (talk) 13:58, 2 November 2022 (UTC)

You're not the first to say so but with all these archives it's hard to notice. Since this keeps coming up we definitely need to explain better that, no, these figures are definitely in gigabytes per second (10^9 bytes per second). The relation between the doubly pumped lanes, bonded lanes, gigatransfers per second and net data rates can be a bit overwhelming at first. Digital Brains (talk) 20:26, 2 November 2022 (UTC)

Alternatively we could just convert everything to bits per second... it's a fairly uncommon unit, bytes per second. But then the problem will be people asking "so if I have a file of 10 GB, how long will it take to transfer?" Digital Brains (talk) 20:34, 2 November 2022 (UTC)

@Bravekermit: I don't see any problem either – otherwise please point to the exact error. @Digital Brains: I don't think everything in bit/s would be very useful. The signaling (encoded) rates in bit/s and the usable (uncoded) rates in B/s is fine imho. --Zac67 (talk) 21:52, 2 November 2022 (UTC)

I think it would be sufficient to have a general footnote something like this:

binary - kilo-mega-giga == 10241 / 10242 / 10243

decimal - thousand-million-billion == 10001 / 10002 / 10003

but industry standard nomenclature will never adhere to convention whenever exaggeration for profit is an incentive. 2601:40D:8100:9400:F5C7:8D0E:66E6:3C06 (talk) 08:48, 5 July 2023 (UTC)

Oh wierd - I must have had too many docs open - this one consistently uses GB/s gigabytes for the useful things. My only suggestion would be to first say what one lane was rather than 16 - but its a minor suggestion... Bravekermit (talk) 13:46, 7 November 2022 (UTC)

"full-size" -- 10W vs 25W

https://en.wikipedia.org/wiki/PCI_Express#Power

the 1st bulleted item says x1 cards are limited to 10W.
the 3rd bulleted item says "full-size"  x1 cards may make a grab for 25W.

but what is "full-size"? it is nowhere defined in this article. that is not an official term.

"PCI Express® Card Electromechanical Specification Revision 2.0" section "4.2. Power Consumption" explains the 10W limitation exists for HALF-LENGTH  x1 cards; those which are less than 7 inches deep. the reason is for heat dissipation via simple convection.

snippet:

Notes: 1. A standard height x1 add-in card intended for desktop applications is limited in length to a half-length add-in card and 10 W maximum power dissipation. A standard height x1 add-in card intended for server I/O applications with 25 W maximum power dissipation must be greater than or equal to 177.80 mm (7.0 inches) in length, but must not exceed a full-length add-in card. See Table 6-1 for add-in card size definitions. The same server I/O add-in card must, at initial power-up, not exceed 10 W of power dissipation, until configured as a high power device, at which time it must not exceed 25 W of power dissipation. Refer to Chapter 6 of the PCI Express Base Specification, Revision 1.1 for information on the power configuration mechanism.

"PCI Express® Card Electromechanical Specification Revision 3.0" section "4.2. Power Consumption" maintains the ordinary half-length  x1 card's 10W limit, but increases other cards' limits to 75W after configuration.

snippet:
• A x1 standard height, half-length card is limited to a 10 W maximum power dissipation.
• A x1 low profile card is limited to a 10 W maximum power dissipation.
• A x1 standard height, full-length card is limited to a 10 W maximum power dissipation at initial power up. When the card is configured for high power, by default, it must not exceed a 25 W maximum power dissipation or optionally it must not exceed a 75 W maximum power dissipation. A x4/x8 or a x16 standard height or low profile card is limited to a 25 W maximum power dissipation at initial power up. When a card is configured for high power, it must not exceed a 75 W maximum power dissipation.


As can be seen, the Revision 3.0 info (circa 2013) substantially supersedes the content in this Wikipedia article https://en.wikipedia.org/wiki/PCI_Express#Power which is at this point woefully obsolete and inaccurate.

Throughput

I want to raise the question of what bandwidth to indicate in the article. It is now listed in one stream, but why?! It's a gross violation WP: OR! In a significant majority of sources, as well as PCI-SIG itself, the speed is indicated precisely in the duplex (in both directions), for example, for PCI-E 7.0 x16 it is 512 GB/s, which means that this is how we should indicate, as the source says, and not engage in unauthorized division into two. Of course, it is necessary to clarify that the speed is indicated in the duplex (in both directions). Wikipedia is written by source rather than original research. --185.52.142.168 (talk) 15:41, 10 August 2023 (UTC)

It's better as it is. To state the maximum throughput per direction is more meaningful to readers and users – there are few uses cases where Tx and Rx are both fully loaded. Adding both directions together is pure marketing from the side of PCI-SIG and it's simply copied all over the news. I don't see any OR as bidirectional and unidirectional values provide the same technical information. --Zac67 (talk) 17:36, 10 August 2023 (UTC)

PCI Express Mini -Pin layout, and voltages

PCI Express Mini Card Pin layout should be included. And, PCI Express Mini voltages are stated 1,5 and 3,3 V, whereas the msata variation is specified 5 V. Could somebody resolve this? 87.185.213.192 (talk) 16:41, 25 March 2024 (UTC)

Broken citation

in slot power 129.130.18.193 (talk) 02:09, 20 April 2024 (UTC)