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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?"
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.
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
Better yet, let's rename PCI to PCI-Express and keep PCI-Express as PCI-Express, and then we'll all have PCI-Express. ;)
My journal has hot
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.
As I understand it, 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.
University - a box of academia nuts.
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)
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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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?
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
Now that's a no-brainer.
My computer is by far not a high-end box, but PCI is a (small) bottle-neck, even for me.
Let's see: 2 IDE channels, 2 disks, that's 50 MB/s each, 1 GBit network, that's peak 100MB/s. A U2W SCSI host adapter with 1 single, very fast disk is good for 70MB/s. Then there is USB2 (everything is USB2 now) and Firewire (each 50MB/s). Adds up to (peak) 370MB/s.
You and me and most people know, that a usual user and most unusual users like the ./ crows will never use all devices at once. But just copying data from disk to network saturates the bus.
A simple fix is 66MHz 64Bit PCI, but those are very rare in consumer machines. So while PCI-Express might be currently overkill, I doubt simple 33MHz 32Bit PCI will be sufficient even for consumer grade computers. Just imagine 10 years ago when PCI started: most were using ISA and that was enough for most usual users. 10MBit/s Ethernet cards used less than 1MB/s. Who needs a faster bus? Only servers needed PCI (or EISA).
Watching the long migration from ISA to PCI until ISA was (mostly) replaced, I don't expect PCI-Express to replace PCI within 5 years. And in 5 years I would bet, that PCI looks like ISA does now: slow and outdated.
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
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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.
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"
> 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
The one consumer-level application where a better bus is vital is HDTV. Current buses are just barely able to handle uncompressed SDTV (20-30MB/sec). (in theory PCI gives you 133MB/sec and AGP more, but as they say, in theory there is no difference between theory and practice :).
PCI-X will finally bring HDTV (~200MB/sec) within reach. What this means is that you'll be able to have a software-only HDTV decoder - which will make it trivial to receive HDTV broadcasts on a PC, and make HD-DVD players possible.
At the pro level, this is just about the last thing that a $50K SGI system has over a cheap Linux PC - playback and maniupulation of uncompressed HDTV video. It's about time PCs finally caught up to "workstations" in the bus department...
You will also need to consider bus efficiency. PCI is something like 60-70% efficient, and PCI-X is about 90%. So 60% of PCI 64/66 is at about 370MB/s. If all your devices happens to run at the same time with your above description you just peaked. However, consumer hardware always lag WAY behind. You are not thinking of enterprise server space where 1GigE is being deployed, fibre channel running at 2GigE, and 10GigE is being developed. Even with PCI-X 2.0 with QDR you may not have sufficient bandwidth eventually. It's a very simple analogy of most home users are still on modem as PCI 32/33, and most of the corporate world is on 10/100Mbps going to GigE as PCI 64/66 -> PCI-X 66-133.
Also, your assumption of 1Gbps peak at 100MB/s isn't quite correct. You have to remember GigE is full-duplex. The theoretical TCP maximum throughput on GigE is about 940Mbps or ~120MB/s. Not that you will ever have traffic full blast both directions but theoretical peak for GigE traffic on the PCI bus would be ~240MB/s.
PCI Express is software compatible. Therefore there wouldn't be any software changes at all to utilize PCI Express. They would be backward compatible and show up looking just like a PCI device. Of course with more features in the PCI Config space just like PCI-X if the software bother to take adventage of them. It really all depends on the OEM vendors on how fast they want to put PCI-E in. But you will see something like back in the days when PCI slowly replacing ISA and now no ISA slots are there anymore.
Moderators on crack. This is just plain wrong. Firewire is 400 or 800 Mbits/s, while SCSI is up to 320 Mbyte/s, IDE is up to 133 MByte/s, and Fibre Channel is up to 250 Mbyte/s. These numbers are directly comparable, because different buses have different amounts of overhead, but for sure firewire is a slow also-ran when talking only about performance. (When talking about cost, flexibility, etc., firewire looks better, of course.) As far as PCI goes, the top end is over 1 Gbyte/s, which is a bottleneck for some applications, but not firewire. Also, in high-end servers you'll have a number of pci buses to improve performance.
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.