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PCI Express - Coming Soon to a PC Near You
Max Romantschuk writes "I've been following the emerging of PCI Express for some time now. PCI Express, previously known as "Third Generation I/O" or "3GIO", is the technology set to replace PCI. PCI has been with us for around ten years now, and is rapidly running out of bandwidth. Last week Anandtech ran an interresting story on PCI Express. The techology has previously been covered by Hexus and ExtremeTech aswell. I feel this technology looks all set to replace PCI, and we really do need some new bus technology to keep up with the bandwidth demands of today's applications. Or is this just yet another way to force us into a new upgrade cycle?"
Due to its high bandwidth, it's expected to replace AGP as well.
"Oooh, does that mean we get to kick some puffy white mad zionist butt?"
Let's start fresh! SATA, PCI-Express, USB2.0! Time for a clean break! Get rid of all the legacy crap. We're supposed to upgrade every three years anyway, so let's really upgrade.
Oh Shit, we all have iMac's now...
You think that I'm crazy, you should see this guy!
Excuse me for being dumb, buy why is everything going serial over parallel? I.E. Why is serial transfer faster than parallel transfer?
Just wait until the PCI group renames PCI Express to PCI just to keep things confusing to the consumer. After all, if consumers are demanding PCI Express in their computers, then just rename everything to PCI express... or however that USB fiasco works out....
I'm just wonering now if that external HD USB2 case I bought is really 1.1 or not... Grrrrr.
If telephones are outlawed, then only outlaws will have telephones.
Or is this just yet another way to force us into a new upgrade cycle?
:)
Or maybe current PCI devices don't support DRM out of the box ? Please upgrade your bus techno, so we can use all this extra bandwidth to transfer huge crypto keys to/from your hardware, just in case you want to play a copyrighted sample on your soundcard
(-1 Paranoid)
Karma cannot be described by words alone.
More than bandwidth, what I need would be a bus
that doesn't have a problem with too many extensions
because of a limited number of IRQs.
Today most mainboard come with many onboard PCI componentes. If you really are going to put in 3-5 extra PCI components in a stock PC, you usually end up in a nice game of 'let's see what order works best', or cannot use all cards together at all.
Is it what the manufacturers think we want? The traditional Hard Drive is still the main componant in the PC slowing everything down, yet the manufacturers still keep increasing CPU, and BUS speeds and increase noise and heat levels.
Why does every /. story need to have some little cynical tagline at the end of the intro. Why can't people just post the story, let other's read it, and formulate their own opinions? Arrgh, it's been starting to drive me nuts. /. is starting to sound more and more like a bad TV news program every day. "Everything is quiet and safe in our little suburb. OR IS IT?!"
Given that the PCI interface was introduced to the world by intel in 1992 and that we since have increased the cpu processing powers by a hundred fold (give or take a little) it is really about time that the bus catches up.
Thomas S. Iversen
I'd say a new standard every 10 years is a pretty reasonably upgrade cycle compared to most other PC technologies...
OK, so yes we can probably live with PCI for longer (possibly much longer), but why not introduce a new standard with better potential? It maintains complete backwards compatability with regular PCI components, so manufacturers of harware don't even have to change anything. Of course another issue is motherboard cost, but there will always be new features put into successive motherboard generations that aren't in widespread use yet... like serial ATA, gigabit ethernet, etc. And there will probably be motherboards available for a lower cost without those features as well.
How are those tiny little serial connectors supposed to support the weight of my 2007 GeForce Maxx Fury 7 video blaster with its jet turbine fan? They'll snap like twigs, I tell ya!
It looks like Linux developers are already working on support. Also, the Inquirer reports that PCI may kill AGP?
Or is this just another way to force an upgrade cycle?
It may well be one of the intentions of it, but one thing I don't get is that with CPU speeds and hard disk capacities where they are now, the average computer buyer (which probably is not very well represented on slashdot) no longer really needs to upgrade their computer, so changing interface/slot shape/etc won't really matter to them.
I know I'm generalising, but the only applications that really push today's computers are games (and high end scientific programs, but they're a fairly minor special case) and I would guess that most computers are not used primarily for games (ie. "serious gamers" - think families). Serious gamers will always be upgrading their computer to the latest and greatest anyway - they don't need to be forced into an upgrade cycle.
It's getting to the point now where by the time the average family decides they need to upgrade their computer, it is easier (and maybe even cheaper) to just buy the latest middle-of-the-line computer package.
I'd almost question whether the idea whole idea of upgrading is itself becoming obsolete for an average computer user?
"Because it's there." - George Mallory, when asked why he wanted to climb Mt Everest, March 18, 1923 (New York Times)
Exactly, check out the i875 chipset design on the 3rd page of the anadtech article and everything there without using pci, with a springdale/canterwood/nforce2 even, motherboard everything but the kitchin scsi is built in, expansion cards are becoming useless on average machines as proved by the huge growth of laptops and small form factor computers. As long as the agp slot keeps up with the pace then graphics cards will be happy and pci/pci-express cards will only be useful for workstation/server machines. Can anyone actually think of a useful expansion card that wouldn't duplicate something on a new motherboard (occasional firewire ommisions and scsi excluded)?
Yup. I just went to look. They have the PDFs avialable, but a password is required. You can sign up for an account, but only if you are an employee of a company which is part of the consortium.
Oh, I'm sure at least a couple of Linux companies will get access to the specs. That isn't a whole lot of help to those of us who are not working on Linux. We either have to wait for the code to be completed and available from Linux (From which we then have to reverse engineer the exact process from) or hunt around until someone leaks the specs and we can snatch them on the quiet.
Don't even bother to flame me and claim that these standards bodies have a right to make money from these; its a damn specification They are funded by the hardware companies who are going to make millions of dollars in upgrades and new hardware alone. Charging a few bucks for the specs is a little on the cheap side.
Based on the direction in which mass-market computers are moving, the bus that gets exposed to the user is getting somewhat less important. Aside from gamers and tinkerers, and people who manage big servers, how many computer users ever have a need to open up the case?
Ten years ago it was almost a given that at some point, you (or your Computer Guy) had to add or replace one of the cards -- add Ethernet, upgrade the video, whatever. Nowadays, the hardware on-board is more than sufficient, and any of those "special" accessories you get, such as storage drives for your digital camera, or a scanner, or whatever, are more likely than not going to be USB or FireWire.
It's very likely that the mainstream desktop computer is going to move to a slotless "brick" form factor. This would have the side benefit of making it much cheaper. This form factor is available already, but it's not yet cheap because it's still considered a "specialty" unit.
I'd also be happy to see the return of the Commodore 64 form factor -- just shove everything into the keyboard. Plug in your mouse and monitor and Ethernet, and go.
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But I like to upgrade!
I usually build two computers a year. If I sell my computer every six months at 75% (which is about the going price) of its original price, I can keep up experimenting with sweet new hardware.
As an added bonus, I've built an expanding network of friends, friends' friends and practically unknown people who have been referred to me by the others. They buy my second hand computers, consult me whenever they want to buy a computer and have me build computers for them. I do it free, although sometimes I ask a steady "customer" to buy me some interesting item as a nominal fee for my services.
It's great fun! Yes, I tend to lose some money but most hobbies will cost you something.
BOO! TERRO
Hmm, let's see, on a desktop PC, you have:
some IDE controllers, each of which can push maybe 50MB/sec to the media (RAID-0) tops.
audio, keyboard, some other I/O, maybe 1 MB/sec
NIC, 10MB/sec tops
Ok, so I do the math and get 61MB/sec, or just under 1/2 the bandwidth of PCI. For 90% of the PCs out there, this is sufficient. For high end boxes, you can use 64bit or 66MHz PCI, or PCI bridges.
Tell me again why this technology is necessary?
I want to delete my account but Slashdot doesn't allow it.
Lets faces it, this is just so we can stream porn faster - everyone knows what drives technological advances. Innovation can be measured in pron per minute...
About the only stuff that has made it into the chipset are cheap soundcards (yes creative is cheap to) and some extremely cheap raid solutions. A lot of other stuff is still in one form or another on the PCI bus. Even if it is not included on a plugin board.
So yes there is a real need for it. Simple example? Raid disks. With striping (multiple disks working together) it is now very easy to saturate the PCI Bus with the cheapest disks.
Same with gigabyte ethernet.
Of course it will be a long time before any real replacement will happen if ever. If I look at some of my old boards on top of the bookclosset I can see it took a long time before ISA was off, and I also see some odd really short slots I never used or seen cards for.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
One high end hard disc delivers 50MB+/s.
One gigabit Ethernet card can do >80MB/s
Together they are limited by PCI.
Now try Raid, TV-Card with PCI-OVerlay, GFX-Cards (Yes, they need a few 100MB/s)...
Plus remember that you NEVER EVER reach 133 MB/S with PCI. Even a single device can be happy to get 110MB with long bursts, and if you have many devices, effective total bandwith is more like 66 than 133 MB/s.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
I believe that onboard devices are still part of the PCI bus, even though they're not plugged into a PCI slot. So onboard Gigabit ethernet will still eat into your available PCI bandwith.
Also, you don't seem to be looking at individual PCI devices rather than the total bandwith for all devices. Right now if you want more than 2 IDE drives and have them not affect each other, you need multiple IDE controllers. Individually they may fit into the available bandwith fine, but combine several and you can be in trouble.
The same can be said with multiple ethernet cards. One gigabit ethernet card may work fine, but if you want to have multiple, you may have issues.
âoeI feel this technology looks all set to replace PCI, and we really do need some new bus technology to keep up with the bandwidth demands of today's applications. Or is this just yet another way to force us into a new upgrade cycle? When I look back at the explosion of technology within the past decade and the ever-continuing attempts to eradicate the bottlenecks that computer systems have had PCI Express is a breath of fresh air. For example lets take a look at processors; within the past ten years processor speeds have doubled every eighteen months if we go by Moores Law. Itâ(TM)s hard to believe it was a little over ten years ago that Intel released the First Pentium Chips. HDD speeds (physical read) have also increased dramatically from about 2 MB/s for a 635MB HDD to over 45 MB/s for a modern HDD. Graphics were given a face lift with the introduction of the AGP bus pushing the speeds of transfer up from PCIâ(TM)s 133 MB/s to 2.1GB/s however many systems are used for a LOT more than video rendering capabilities and are geared more towards storage markets were data access speed is of the utmost importance. 64 bit PCI gave us a boost to 266 MB/s transfer speeds to be used in conjunction with high speed U320 SCSI but even then we cannot take full advantage of the capabilities offered. PCI express opens up the horizons for computers letting us transfer substantial amounts of data in less time. This can only be a good thing. More Information * Shorter Time = Greater Efficiency Therefore I donâ(TM)t see this as another way to force us into the upgrade cycle but a good solid advancement in computers. Also, the good thing is that it is coming wither we like or not.
- Sig
Server hacks like the 66-MHz PCI bus speed and 64-bit-wide PCI are neither practical nor sustainable. That's why we need something different, something like PCI Express. It raises the I/O bar enough to give us another few years of unconstrained growth of the PC architecture.
Easy, automatic testing for Perl.
The real PCI bandwidth is usually something like 75-90MB/sec. Depending on the chipset.
Now, add in IDE RAID cards, and SCSI cards and those along can saturate the bus. Consider that a single SCSI HD can now pump out about 70MB/sec when used in an STR intensive application.
If you think education is expensive, you should try ignorance -- Derek Bok, president of Harvard
using serial there is no having to worry about whether all the bits arrive at the same time (as there obviously is with parallel), and so the speed of transmission can be dramatically increased past the point at which it becomes faster than the "equivalent" parallel technology... bits arrive in the order they were sent - guaranteed.
:-l
I'm afraid this might add to the confusion about serial interfaces being 'faster' than parallel. While it is true that you don't have to worry about data/clock skew when using serial interfaces, enabling you to clock them faster, a parallel interface running at the same clock speed as a serial interface will always be faster in terms of data throughput. The reason for this is simple: serial == 1 bit per clock, parallel = > 1 bit per clock.
So, saying that serial is faster than the "equivalent" parallel interface is confusing, and incorrect, because one could be referring to equivalent clock rates being used for each interface, in which case parallel will provide at least twice the data throughput. On the other hand, "equivalent" could be referring to identical throughput rates, in which case the serial and parallel interfaces would provide, by definition, identical data rates.
The real advantage that PCI Express has over PCI/PCI-X is that it is a point-to-point, rather than a multi-drop, bus. This setup requires less time between pin transitions, meaning that it can be clock faster. Also, like Ethernet, a serial protocol can imbed the clock into the data stream so clock/data skew is no problem whatsoever.
Serial is not better than parallel anymore than digital is better than analog, there are just physical reasons why implementing point-to-point serial at significantly higher clock rates is easier than multi-drop parallel.
Anyone still awake?
Didn't think so
If it's not one thing, it's Steve's Mother
We realized PCI wasn't going to be fast enough years ago-- that's why pretty much every motherboard you can buy today has an AGP socket.
And even that wasn't fast enough, now we have AGP 8x.
But seriously, is PCI really not fast enough for the general consumer, once he's got an AGP socket? PCI that runs on a 66MHz bus that's 64 bits wide has existed and even been available in high-end PC class hardware for years, but few of even Slashdotters have anything other than 32 bit 33MHz PCI in our home machines. The only time I ever deal with the 64 bit PCI cards is for Sun Microsystems hardware at the office.
I don't think this is "forcing another upgrade cycle" at all-- upgrades already exist, and most of us don't have 'em.
I suspect this will be a long attrition as it was with phasing ISA out of motherboards.
From the Anandtech article:
So, for many users PCI-Express will not be a necessity because the unwashed masses are by and large not on the cutting edge of the sort of technology that demands it. The early adapters will drive the market and the rest will follow along when there is a pressing need or when the industry drives us there, e.g. when we can't easily get motherboards or cards without it. I am a fairly cutting edge user and it has only been in the last couple years I switched off the last machine at my house with an ISA slot.
If, as stated elsewhere, this will outperform AGP, then hardcore gamers certainly will go there, but who needs to force an upgrade on them anyway?
Trouble making decisions? Just flip for it.
So get a high-speed parallel printer port card, a high-speed serial port card, or a USB microcontroller development board.
-- ;-)
Kuro5hin.org: where the good times never end.
Never again will any announcement of new hardware technology be received by us geeks with the glee it once was. The only thing that comes to our minds now is "great, another opportunity for them to add DRM and phase out hardware that allows copying"
The vast majority of users will not have any need for this kind of bandwidth for quite a while. People doing heavy graphics/video processing will like it but 99% of the public will yawn.
There are two major benefits, however.
Adoption will be fairly fast because so many facilities are built right on the motherboard today. Since much of the market never installs a PCI board, there is nothing preventing them from buying a PC based solely on this new technology, particularly since the new hardware won't be expensive.
And the economies of scale in sharing more hardware throughout the line from consumer PCs to high end servers will be good for everyone. Now we'll be able to steal more equipment from work (just kidding).
I'm watching to see when the processors start talking serial directly. Getting rid of the exotic seven thousand pin packages for processors (and their associated sockets) will be another great savings.
> What PCI device are you using that is bandwidth limited & will benefit
:P
> from a faster PCI bus?
Gigabit ethernet, soon 10gbit ethernet..
multiple firewire buses, or even one firewire 800 bus..
Multiple high speed graphics cards..
Multiple SCSI or fiberchannel buses..
> I don't have anything.
> I really have nothing that will gain any benefit.
Well thank you for deciding that what you need is exactly what everyone else needs and they should be happy with that
And 640 KB is more than enough memory for any desktop too,
Try thinking new applications. What if your "desktop" machine is capturing one TV show, downloading a major update to a software application, and your viewing two versions of a video in parallel in order to determine how to further edit the thrid copy that you have open in another window.
And oh yes, you just received 73 wonderful opportunities to engage in financial transactions with a former Nigerian minister.
It seems to me that a "desktop" machine could end up needing quite a bit of internal bandwidth.
This is a very cool feature in the new Intel 865 and 875 chipsets (the ones that support the 800Mhz front-side bus) -- the onboard gigabit LAN port is on the Northbridge, not the Southbridge, so it's not contending with PCI for bandwidth.
As far as I know, this is the only currently-shipping chipset that does this.
SCSI and fibre channel drives have used SCA (single connector attach) for years. Telephone and realtime control industries are big on cPCI also. But the reason isn't to make it easy to install hardware, its because the servers run an OS that supports hot plug. The goal is zero downtime, even for maintenance.
Standard PCI is laughable for high availability.
Parity is for farmers -- Seymour Cray
- IDE harddrives (up to ~60MB/s)
- AGP graphics card
- Fast ethernet LAN (10MB/s)
PCI does 133MB/s.IDE chips are onboard and don't need PCI slots.
Gigabit ethernet could be a use of buses faster than PCI but I've felt the trend is also to put them right on the mainboard. Besides, the switches are still prohibitively expensive.
AGP: We've seen that 8x AGP does not give a performance boost over 4x AGP.
I don't see a great need for PCI-X at the moment.
I scanned the articles checked for anything on this, but didn't find a suitable answer. Will "PCI Express" be like USB, wherein it will support the older gen hardware as well as the newer hardware - or it will only support "Express" PCI devices?
It would be very nice to maintain a PCI port that was capable of faster speeds but still able to run old devices (somewhat like AGP 2x/4x/8x or USB 1.0/1.1/2.0 ramping up, ignoring recent USB developments).
I still remember one of biggest pains in my backside was trying to run PC's that needed an old ISA device (Scanner interface, old ISA SCSI card, special controller card, whatever) which I have heard is a drag on the whole system. Nowadays, I've got only PCI and AGP, though my old but still very good ISA SCSI scanner is still plugged into my 1Ghz Duron (with a single ISA port).
Will we get the best of both worlds? If express supports normal PCI, we can replace the old stuff in a jiffy. Running mixed slots again might be a pain, though.
PCI has been with us for around ten years now, and is rapidly running out of bandwidth
Are you *sure* it's running out of bandwidth?
The old-time, 10-year old 33 MHz, 32-bit PCI bus is still handles 99% of all home users just fine. However, for the more bandwidth-hungry users, you can increase the width to 64 bits. Not enough? Double the frequency. Still not enough? PCI-X will run them at up to *133 MHz*.
Let's put some numbers to that. On a 32/33 bus, you're looking at a maximum real-world, sustained throughput of about 100 megabytes/second. Double the width, that's 200 megabytes/second. Double the frequency, that's 400 megabytes/second.
Alrighty, then. Nearly a half of a gigabyte per second. That's awfully tough to fill. That will handle two gigabit ethernet controllers running full-tilt, and still have enough bandwidth left over that you'd need at least an INCREDIBLY fast RAID array to fill it.
But, just for fun, let's say it's still not enough. PCI-x, at 133 MHz, will double that *again*, to a full gigabyte per second. On a single controller. You're going to have an *INCREDIBLY* tough time actually using that - you'd be very hard pressed to actually get that much to move over a network and/or disk.
Still, you need more? No sweat. Many boards offer more than one controller. With two PCI-x controllers, that's two gigabytes/second of bandwidth. Not two gigaBITS, but rather two gigaBYTES.
Tyan recently introduced a board that has four gigabit controllers, each on their own PCI-x controller, with an additional 64/133 controller, a 64/100 controller, and a 32/33 controller. Again, let's put some numbers to that:
At 100 MB/s for each of the gigE controllers, that's 400 MB/s right off the bat. Add in the 64/133 controller, that's about 1400 MB/sec. Add in the 64/100, you're looking at about 2200 megaBYTES per second.
Now, really... can *anyone* here raise their hand and say that they could actually *utilize* 2200 megabytes/second of bandwidth to the outside world, either via network or disk?
Despite all of the ideas of the sky falling, PCI has done a very good job for the last decade, and amazingly enough, is still going strong. Strong enough that it will be quite a while before it truly NEEDS to be replaced.
Now, when it *IS* replaced, I'd much rather see the interconnects being optical, not electrical. Instead of cracking open the case, shutting off the power, and trying to wedge yet another card inside (especially in low-height rackmounts), I'd much rather set the device on a shelf, and run a fiber patch cable over to the computer. No shutting down, and a whole lot more simple.
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
Well, it's more than one ISA slot, but at least they're there...