What's this PCI Xpress I hear about?

[Deagle]

Well I was at another PC forum and they were talking about the next replacement for the AGP slot will be the new PCI xpress slot. Is this true? If it is then what will be next, an AGP xpress slot?
Can someone confirm this please?
Thanx:D

[saphalline]

Yeah, it's Intel's answer to the next expansion bus that will be needed. PCI, ISA, and even AGP are coming to the end of their useful lives. Not to mention everything that goes along with that (*cough* backwards compatibility *cough*) so PCI Xpress will replace all current expansion busses. At least, that's what Intel's plan is.

AMD has their own ideas. Can't remember the name exactly, something like "IGIO" or whatever. I also can't remember the specs on these new busses, but I'm sure someone will look it up. I'm just being lazy right now...

[Whyzman]

I'm just being lazy right now...Sheesh! :D

[malcore]

PCI Express will probably debut in the second half of next year.

Intel started it with a few other companies (Microsoft, Dell, Compaq, IBM). AMD was working on HyperTransport, but hopped on the PCI Express bandwagon. It is also known as 3rd Generation I/O or 3GIO and Arapahoe.

It is serial based, whereas PCI buses as we now know them are parallel based. It will dramatically increase available bandwidth for firewire, USB 2.0 and Gigabit networking.Even ATA133 can overload the present PCI bus.

AGP 8x will probably be the last AGP standard.

I'm sure microsoft will cash in on this with Longhorn.

[saphalline]

Ok, I found the article where I saw this new PCI standard (Max PC, Sept '02) and they have a lot of info on this.

The PCI Express protocol seeks to use the existing PCI traces (the actual leads on the mobo) in a new way. It will still be 32-bits wide, but instead of being treated as one parallel interface, each bit will be treated separately. In essence, this creates 32 serial busses next to eachother. Each bit or "lane" will have 2.5Gb of bandwidth per second in each direction! :eek: This amounts to a total bandwidth of 80Gb/s (or 10GB/s) in each direction! What's more, future versions expect to scale this up to 10Gb per second per "lane"! :D

In addition to the astounding increase in bandwidth vs current PCI, the "lanes" can be doled out in chunks - 1, 2, 4, 8, 16, and the full 32. And since most expansion card devices will only need (and be given) one lane, any device that uses other lanes will get the full bandwidth. No more sharing of the whole PCI bus between PCI cards & IDE devices, they can each be given a lane or two for themselves. This is especially nice since 1) hard drives are moving over to SATA so only optical drives will be left to share the bandwidth with expansion cards (and these require very little bandwidth) - 2) there is no more wasting of resources since each lane is separate and can be given to a device individually - and 3) best of all, this means an end to the antiquated IRQ system!! :D :D :D

The PCI Express bus, with its improved design and eventual scalability, will also replace AGP 8x in a couple years. At roughly 5 years old, the AGP bus certainly isn't the oldest bus in a PC, but considering how fast & furious the graphics industry has been moving, it's definitely showing its age nearly as much as a parallel port! AGP 8x gives us a nice boost for now, but if ATI and NVidia realize their dream of better-than-Toy-Story-graphics any time soon, even AGP 8x will be screaming for mercy! Enter PCI Express, where video cards are expected to be given a full 16 lanes to themselves, for a total bandwidth of 40Gb/s both ways. :D Nice.

Finally, we can get rid of the old busses and ports and connectors that have plagued PC's for the last few years. I say only "the last few years", because before that, they weren't a plague! They were useful! Anyways, it won't be a total loss because if you really need a PS/2 port or serial port or any other PCI or ISA bus-based connection, I'm sure they'll make a PCI Express expansion card with the 'oldies' on it! ;)

[malcore]

We're probably talking about a whole new form factor as well. Look at this "Bigwater" layout:

http://www.hardwareanalysis.com/images/articles/small/10671.jpg

Notice the CPU in the bottom left with direct intake through the front!!(or is that exhaust through the back?) Big changes!

This may be the new form factor when Intel's Grantsdale chipset emerges late next year.

Anadtech has a very recent article (June 12) here (http://www.anandtech.com/systems/showdoc.html?i=1830&p=1)

[karatekid3d]

I think this was hinted on but from what i read PCI-Express will be backwards compatible with existing PCI. The difference is that there will be a small extra connector add-on. Kind of like when EISA came out how it still supported ISA cards, but if your wanted an EISA card it would have that little extension.
http://images.anandtech.com/reviews/system/pciexpress/pci-ex-ext.jpg

Also keep in mind that this technology is going to extend to notebooks/laptops as well:
http://images.anandtech.com/reviews/system/pciexpress/newcard-sw.jpg

http://images.anandtech.com/reviews/system/pciexpress/newcard-dw.jpg

[ErnieK]

So what KK3d is saying is that our existing PCI and AGP card will still be usable?

Also will existing HDD's and (I know some say they are already defunct) Floppy drives be able to operate with this new arcitecture?

[karatekid3d]

Originally posted by ErnieK
So what KK3d is saying is that our existing PCI and AGP card will still be usable?

Also will existing HDD's and (I know some say they are already defunct) Floppy drives be able to operate with this new arcitecture?

One thing to keep in mind is that often when motherboards are making a transition from one technology to another, both the new and old technology will be offerd on the same board. For example when PCI was starting to take over EISA you would frequently see boards with both slots offered. Another good example is when boards were switching from SIMMs to DIMMs or even now with both SATA and EIDE connections being offered. So you might see a board with PCI-Express and an AGP slot offered untill PCI-Express becomes the dominate technology.

What i'm not too sure about is, say i have a regular PCI card installed and a PCI-Express card installed, does my entire expansion bus go the speed of the slower PCI card? That would be kind of like how if a USB 1.1 device and a USB 2.0 device are connected on the same controller, both will go the speed of the 1.1 device.

[rond36]

Is PCI express the same as PCI-X slots that newer workstation and server motherboards have. If they are the same they are not backward compatible with 32 bit 33MHz PCI slots. I am thinking about building a duel processor system. The board I am planning on using is the Supermicro X5DAL-TG2. (http://www.supermicro.com/PRODUCT/MotherBoards/E7505/X5DAL-TG2.htm) More on that in a different post. :D

http://www.supermicro.com/Product_page/MB-Pics/E7505/X5DAL-TG2.jpg

It has
1 4X/8X 66MHz AGP Pro slot (brown)
2 32 bit 33MHz PCI slots (short white)
1 64 bit 100MHz PCI-X slot (long white)
1 64 bit 66MHz PCI slot (green) for the DAC-ZCRINT PCI zero channel S-ATA RAID controller but can be configured as a second 64 bit 100MHz PCI-X slot

There is no way a 32 bit 33MHz PCI Card is going to fit in a 64 bit 100MHz PCI-X or 64 bit 66MHz PCI slot.