What's PCI Express?

[tinydancer]

What is PCI express? If I am not mistaken I have read various thread that mention pci express, which evidently differs from pci. Is this correct? If so, how so? If one is going to build a system, should this capabiltiy be included now, or is this technology around the corner?

[Converted2Truth]

To put it simply, PCI express is a serial version of the old PCI bus (which was parrallel) The benifit? separate pipelines for data heading to and from the bus (in the oldschool PCI [including PCI-X] the data going to and fro shares the same data path)

This new method effectively increases bandwidth... allowing communication to and froe simultaneously.

Personally, i don't get what the big deal is. Maybe for people that are playing doom3 off their vcard, while they're rendering something off a SATA card in their PCI slot...

But for all normal operations, there's really no need for this type of bandwidth increase. I'll leave myself to the wolves now... here it comes...

[combatcolin]

What Apple should better put in the next G5's :mad:

[HiRez]

But for all normal operations, there's really no need for this type of bandwidth increase. I'll leave myself to the wolves now... here it comes...There are a lot more advantages to PCI Express than just more bandwidth (although, yes, of course it's going to benefit power users more than Granny Web Surfer). I thought it sounded lame at first too, but now I'm actually holding off on buying a dual G5 until they have PCI Express in them. It's really a huge upgrade to PCI/PCI-X that has many implications. You can find out a lot more than you ever wanted to know about it in this Ars Technica article (http://arstechnica.com/articles/paedia/hardware/pcie.ars).

[benpatient]

it isn't really an upgrade to PCI or PCI-X.

it's the next phase for the graphics card world, it is the replacement for AGP, not for PCI.

Benefits are, however, considerable.

PCI-Express is to AGP what SATA is to PATA...an evolution. It's simply a more advanced format.

It is to graphics what DDR2 is to RAM.

more sophisticated.

[combatcolin]

How many pci - x cards are actually out there, 7??

66Mhz pci is good enough anyway.

[Catfish_Man]

How many pci - x cards are actually out there, 7??

66Mhz pci is good enough anyway.

PCI-X is totally different. All new graphics card have PCI-E versions, for example, since AGP is being phased out. Since it's also going to replace PCI and PCI-X, it will allow for multiple graphics cards, and since it's bandwidth is the same going both directions (AGP is heavily weighted towards sending data to the card), it will help with the graphics offloading that operating systems are doing more and more now.

[vraxtus]

What is PCI express?

A new graphics fad.

[tinydancer]

A new graphics fad.

Ok, but does PCI ex differ from regular PCI by the slots some how changing or does something different go in the slot. Im asking because I am thinking of building my own gaming rig and wondered if I should make this PCI ex a option when laying out my system, with regard to a motherboard. I don't even know if this is an active technology or if its on the table.

[Converted2Truth]

What is PCI express? If I am not mistaken I have read various thread that mention pci express, which evidently differs from pci. Is this correct? If so, how so? If one is going to build a system, should this capabiltiy be included now, or is this technology around the corner?

It works with normal PCI cards. BUT AN AGP CARD WON'T WORK. The new bus is connected to identical PCI express slots (which are compatible with normal PCI cards). This means you can stick a ATI 9000 PCI in it if you wanted... But i'd recommend you start some SLI action ...courtesty of NVIDIA (and you're think wallet) baby...

[Bigheadache]

PCI cards will not fit in PCI Express slots. A PCI Express x1 slot is about 20% as long as a normal PCI slot. If you want to see what it looks like, do a google search for NForce4 motherboards like MSI K8N Neo4 or anything using the Intel 925 chipset. A PCI Express x16 slot which is what vid cards will plug into and is about the same length as a AGP Pro slot.

Apart from being serial, the PCI Express x16 slot is bidirectional. On a pc, this doesn't help games, but alot of prosumer video editing solutions such as Pinnacle's Liquid range or better use the GPU to render and these will be the main initial beneficiaries.

As to whether its a big deal or not, thats a really moot argument. The PC industry is transitioning, which means vid cards and companies making sound cards, RAID cards, etc, will also transition. That means Apple will have to adopt it at some stage unless they don't want NVidia or ATi GPUs in 2 generations time when those companies completely drop AGP. Besides that, considering Apple uses Hypertransport (a serial technology) as the main system bus and has adopted SATA (another serial technology), it makes sense to adopt PCI Express.

[combatcolin]

pci - x is dying anyway, never really took off.

Within a year pci express will rule the high end graphics card market, AGP will soldier on in the entry and mid range for years to come though.

And Look at the small but strangly constant release of pci graphics cards .

[risc]

PCI cards will not fit in PCI Express slots.

I work with x86/x86-64 servers / workstations all day, and I can tell you we have boxes at work with dual PCI-E/PCI-X slots (same slot).

UPDATE: I'm a TARD the boxes we have here riser boards to convert the PCI-X to PCI-E, please forgive my tardification! :rolleyes:

[risc]

pci - x is dying anyway, never really took off.

Maybe on Mac hardware but in the x86 and x86-64 server/workstation world nearly all cards (non-graphical) are PCI-X, and it isn't anywhere near dying.

[benpatient]

um....

someone must be confused....

Here you will see the two ports...PCI-Express and PCI-X.

The image with PCI-Express is showing one PCI-Express 16x and one PCI-Express 2x lane on a motherboard.
http://www.beareyes.com.cn/2/lib/200402/18/078/PCI-Express.jpg

The PCI-X image shows PCI X and standard PCI slots. These are not compatible concepts...

http://www.highend-funsite.com/SCSI/part5/PCI_X.jpg

You can't just stick PCI cards into PCI-Express slots. That's silly.

You can't stick a firewire cable into a USB port or a ZIP disk into a 3.5" floppy, can you?

They're fundamentally different. PCI and PCI-X are parallel technology...like, as I said before standard ATA is a parallel technology. A single PXI-Express 2x slot will send more information serially than even a PCI-X slot will send...and it's like 1 inch long. Look at the first picture...

You've probably all seen SATA cables and standard ATA cables...you may not know this, but SATA cables are good for like 1GB/second at their final theoretical spec (we're on level 1 right now, 150MB/sec)

here's a site that explains PXI-Express pretty well...you'll see what I mean about the incompatibility.

ed: oops, forgot the link!

http://www.neoseeker.com/Articles/Hardware/Features/pciexpresstech/index.html

[Bigheadache]

I work with x86/x86-64 servers / workstations all day, and I can tell you we have boxes at work with dual PCI-E/PCI-X slots (same slot).

UPDATE: I'm a TARD the boxes we have here riser boards to convert the PCI-X to PCI-E, please forgive my tardification! :rolleyes:

You're forgiven :)

BTW, can you post a pic of these riser cards. PCI Express are Serial technology whereas PCI-X are Parallel. I would not have thought that it is possible to convert them like that without some sort of bridge chip design. (A bit like AGP Tunnels on AMD Athlon64/Opteron designs)

[cube]

What Apple should better put in the next G5's :mad:

And I will hold on until it has 2 x16 slots for SLI. I was dissapointed by the nForce4 SLI. The two fast slots are only x8.

[Bigheadache]

And I will hold on until it has 2 x16 slots for SLI. I was dissapointed by the nForce4 SLI. The two fast slots are only x8.

Thats only because the Nvidia chipset has a max 20 lanes to divvy up. This is a design restriction in the NVidia chipset, not a general rule about SLI. The VIA chipset supports 22 lanes I think, not sure what the Intel Tumwater chipset supports. If you want 2 x16 slots then you'll need to look for a chipset that has over 32 PCI Express lanes.

[cube]

Thats only because the Nvidia chipset has a max 20 lanes to divvy up. This is a design restriction in the NVidia chipset, not a general rule about SLI. The VIA chipset supports 22 lanes I think, not sure what the Intel Tumwater chipset supports. If you want 2 x16 slots then you'll need to look for a chipset that has over 32 PCI Express lanes.

Yeah, I know. VIA is preparing chipsets for both Athlon 64 and Pentium 4 that should be available before the end of the year.

[Sun Baked]

PCI-X is just a clock boosted version of PCI running at top speeds of 100/133 MHz

PCI-X 2.0 takes the PCI slot concept to the next clock level adding 200/266MHz.

Nothing significant, but leverages developers existing technology by allowing them to support higher clock speeds with the same card -- if they have some flexibility in the original card -- without redesigning the card.

Basically speed bumping PCI cards.

---

PCI-Express is a new bus, and will require a new design or something along the lines of the original FW400-to-IDE bridge chips. ie, something quick and dirty to leverage their old designs, but not quite up to full PCI-express speeds because they're using a PCI-to-PCI-Express bridge chip in the first generations.