PCI/E question

[Krusty]

I have been looking at motherboards for a while now. I've been trying to decide about PCI Express vs standard AGP and PCI slots. Most say the same thing about PCI/E

"PCI Express is the latest I/O interconnect technology that speeds up the PCI bus. PCI Express features point-to-point serial interconnections between devices and allows higher clockspeeds by carrying data in packets. This high-speed interface is software compatible with existing PCI specifications."

(blurb from tigerdirect, if I recall where I copied it from)

Okay, so I'm a bit confused. It's a new technology, sure. It's great, I bet. But what about my computer now? I've got every bay in the back of my computer filled right now. Granted I don't need the SCSI card if I get a new HD. And one is just the joystick gameport from an Audigy card.

At first I thought they were incompatible. Then I saw the blurb I pasted above and looked at that small PCI/E slot, and thought "Hrm.. isn't there a notch in standard PCI cards right about where that socket ends? I checked one of my spare parts and found out there wasn't.

Here's the thing... most PCI/E mobos don't have that many slots! Whereas I get 5 PCI and an AGP and an ISA (for backwards compatibility, no doubt) on my current mobo, the majority of PCI/E mobos have just 1 16x slot (reserved for 3D card, no less) and usually just 2 1x slots. Nothing else.

I came across the abit "lethality" AA8XE motherboard and thought "that's better than most" but the problem I have is the PCI/E slots!

What, if anything, uses it? I know it's a step to the future, but is it a step that's going to be around for years and years? If it's so hot, why can't they make it reverse compatible (make it have a larger slot, and be able to communicate with older, standard, PCI cards)?

Thoughts?

[StarOfAfrica2]

PCI and PCI express are not the same thing and are not interchangeable.  So no your PCI cards wont work in a PCI express slot.  And they havent really developed hardware for any PCI express cards yet except the video cards.  Probably next year.  

PCI express motherboards have PCIe slots (in whatever combination you like), and standard PCI slots for your hardware.  SLI boards will probably have 2 of the x16 slots, and maybe a x1 slot as well, plus the standard PCI slots.  An AGP motherboard has the AGP video slot, plus standard PCI slots.  No matter what type of video, they all still have standard PCI slots, they have to.

[Krusty]

No, they don't, lol

I've been looking all day. I've found there ARE PCIe boards that have 3/4 old PCI slots, in addition to 1 PCIx16 (video) and 2 PCIx1 (small slot).

But there are quite a few that only have 1 PCIx16 and 3 PCIx1. No PCI slots.

And the SLI mobos I've seen have 2x PCIx16 and 2/3 PCIx1, but no PCI.

I've decided that for the sake of keeping all my old cards, I need a PCI/AGP combo. The Gigabyte 8IP775-G has caught my eye. I'm thinking of pairing it with a P4 3.0GHz and a 400w psu (mine is about 250 now), plus a single stick of 1024 module DDR 400 PC3200 (my PC133 ram I have now would be useless).

Total price for Mobo/CPU/PSU/RAM = about $450.00. Now to get that $450.00.


EDIT: add $60 more for a 80GB HD, as my current 5-year-old 20GB is rather full.

[StarOfAfrica2]

Wow.  I dont know what they are planning to do with an all PCIe motherboard, unless it has everything else onboard.  I suppose if it has built-in LAN and sound, and uses a riser card modem, they could cover all the bases.  But I dont know why you would need a motherboard that has that many PCIe slots if they try to keep you from having to put in add-on cards.  Thats not good marketing.  

If you want to stay with the AGP, most of the major motherboard manufacturers are going to be making them as low and mid-range replacement boards for awhile yet.  And I seriously doubt there is going to be a sudden dearth of AGP cards available either.  I have already noticed some companies redoing the packaging on the lower end cards to push them toward home office use and video editing instead of gaming.  Which just reaffirms my belief that they arent doing away with it completely anytime soon.  Besides, the PCIe stuff on the market now cant go any faster than the AGP anyway.

[Krusty]

Actually, PCIe is a new interface entirely. It can and does transmit more data than AGP (even 8x agp) can. The thing is, can anything currently available tap into this? Aside from super-high-end-really-costly-3D-cards, no, nothing can.

That being said... I think it's a technology that's before its time. There is the select minority that can afford anything to use with PCIe


Oh, and yes, most of the PCIe only cards I've seen have integreated motherboards, integrated gigabit lan, sound (sometimes 5.1 surround, no less) and USB. All you need is a video card, which they have for PCIx16

[Overlag]

the thing AGPx8 and PCI express x16 is designed for CHEAP gfx cards, that use the SYSTEM ram. However since the fast gfx cards we use have 128-512mb ram on them they dont really need to use the bandwidth available.

 Thats why ATI and NVidia now have those new cards that have a 16-32mb local buffer then use system ram for everything else. These cards cost like almost nothing......


Anyway a performance gfx card wouldnt want to use system ram. System ram = 0.30 to about 0.8gb/s where as there onboard ram is often in the 33-40gb/s range......

[Kev367th]

Originally posted by Krusty
Actually, PCIe is a new interface entirely. It can and does transmit more data than AGP (even 8x agp) can. The thing is, can anything currently available tap into this? Aside from super-high-end-really-costly-3D-cards, no, nothing can.

That being said... I think it's a technology that's before its time. There is the select minority that can afford anything to use with PCIe


Oh, and yes, most of the PCIe only cards I've seen have integreated motherboards, integrated gigabit lan, sound (sometimes 5.1 surround, no less) and USB. All you need is a video card, which they have for PCIx16

Not just that Krusty -
1) No CPU can currently push stuff to the GPU on the latest cards fast enough. So if you have a 6800GT, 9800XT etc or above, we're going to be CPU limited for a wee while yet.
2) In case number 1 therefore the available bandwidth can't be used anyway, PCI-E or AGPx8.

Thats why SLI setups aren't showing the big performance that they could be, CPU limited.

[Krusty]

Not so. The bandwidth isn't for ram.. it's for loading textures into the card.

If you notice, EVERY single new PCIe card is top of the line expensive-as-hell and already has 256 (or some 512) MB of VRAM on the card.

The problem isn't ram. It's sending to that ram fast enough to fill it up. PCIe won't help any low end cards. They simply don't NEED that much bandwidth to the mobo. But cards that run super fast and have super amounts of memory on them, they need to exchange that memory content repeatedly over and over and at fast speeds.

I.e. what's the use of a card that can refresh 512MB of ram every cycle, but you can only transmit 128MB of textures TO that ram every cycle?

It's for high-end, nto low-end. *that* much I know.

EDIT: Kev, interesting. I heard that AMD is making a dual-core chip, but that it had some setbacks. I think. Or that ASUS stopped production on a dual chip mobo that would be able to run 2 of these dual-core chips (4 processor!!!). They're working on it, but they're not there, like you said.

[Kev367th]

If you look at every benchmark for the latest cards, PCI-E and AGP, they all come to the same conclusion - CPU limited. The available bandwidth even on the AGPx8 bus is nowhere near being utilised fully.

The only performance gains for SLI setups are at high resolutions with high AA/AF settings.
Because there are 2 cards doing the work, not because they suddenly started using lots more of the PCI-E bandwidth.

Until we get some sort of Quantum leap forwards in CPU performance, being limited by the CPU is with us for a while.
I think thats why both Intel and AMD have decided not just dual core but multi core CPUs are the way forward.


Krusty - Dunno where you heard that.

Just ordered my AMD64 dual core (X2 4400), be here this week. Fits into my current mobo with a BIOS update to recognize it. (already done).
You may be thinking of a dual CPU/dual core socket 939 board that I haven't heard about yet.

Dual core X2 ONLY ever intended for a single CPU setup, they are missing the extra pin of the Opterons to allow multiple processors.
So I can't ever see a socket 939 multi CPU board.

Current Opteron socket 940 multi CPU boards can take the dual core Opterons though. In fact AMD showed off a 4 way dual core setup (8 cores) way back in January.

Current predictions are quad cores in 2007. (new socket though )

[Krusty]

I think it was a mobo that got delayed. I had an online friend that was going to make a dual chip mobo (each with 2 cores, 4 total) but his plans fell through because either the chip or the mobo was held up. Must have been the mobo.

I am slightly disheartened to see, however, that the future of personal computing is going the way of mainstream liquid cooling. You're adding more and more guts to a chip, and the run hot enough without multiple cores, sooner or later (sooner is my bet) we're going to need some SERIOUS cooling for even a standard setup.

My prediction.

[Overlag]

krusty, they DO also allow system ram to be used by the gfx card, it isnt just for loading textures but virtualy no cards need that

[Kev367th]

Originally posted by Krusty
I think it was a mobo that got delayed. I had an online friend that was going to make a dual chip mobo (each with 2 cores, 4 total) but his plans fell through because either the chip or the mobo was held up. Must have been the mobo.

I am slightly disheartened to see, however, that the future of personal computing is going the way of mainstream liquid cooling. You're adding more and more guts to a chip, and the run hot enough without multiple cores, sooner or later (sooner is my bet) we're going to need some SERIOUS cooling for even a standard setup.

My prediction.

Cooling - Yup, sooner or later, probably sooner, liquid cooling will become the standard.
Even with lower speeds and multiple cores its still gonna generate a hell of a lot of heat.

Mobo - He should have just gone dual cpu, dual core Opterons, there will never be an X2 dual CPU board, they're just not setup for it.

[StarOfAfrica2]

Originally posted by Krusty
Actually, PCIe is a new interface entirely. It can and does transmit more data than AGP (even 8x agp) can. The thing is, can anything currently available tap into this? Aside from super-high-end-really-costly-3D-cards, no, nothing can.
 

As Kev said, nothing out there now even takes advantage of the AGP 8x setup.  They couldnt fully saturate the AGP/PCI bus setup, what makes you think they will utilize a supposedly faster setup anytime soon?  And while theoretically a x16 PCIe slot can transfer data faster because of the parallel, two way communication of the PCIe setup (a PCIe x16 video card slot should provide a useable bandwidth of about 4GB/sec. vs the 2.1GB/sec. bandwidth of the 8x AGP slot), in reality x16 PCIe slots are proving slower than the previous AGP version.

And its not really a "new" technology.  Its more of an evolution of existing technology.  One that still hasnt hit its stride, and wont for some time  yet.  Alot of what will determine how fast PCIe can become a true improvement on existing technology speeds will relate to the advancement of CPU design (again mentioned by Kev).  But more than that, its going to be measured by how much the new dual-core processors open things up (or not) once 64-bit operating systems and programs become available.  I see alot of people hopeful for what 64-bit can do for performance, but I also hear Skuzzy's warnings that Microsoft's intentions on that score do not bode well for those hoping to see big performance increases.  It could literally take years before consumer reaction sets in enough to cause changes that will free up the hardware we see coming now to be useful enough to break the barriers we want to see broken performance wise.  In other words, dont get your hopes up.

[Schutt]

Sorry guys, i have to disagree here.

1. Almost all PCI express boards that are in the medium or good quality range have the old PCI slots too. Abit AA8XE has 2 PCI slots, Asus P5D2 Premium 3 PCI slots, MSI K8N Neo4 Platinum 4 PCI slots, where the later one is a AMD the other two intel.

2. All new AMD 939 that support "venice" core can also take the dual processor cpus that amd will bring out (AMD 64 x2).

3. PCIe x16 offers more bandwidth than AGP. True is what others say... eaven the next generation graphics cards dont use the bandwidth and you get virtually the same speed on PCIe and AGP.

4. PCIe gives a boost to low end graphic cards that use the system memory.

5. The onboard sound is almost always low quality, so no matter how many channles it has it eats up cpu frequency and is worse in quality than a good soundcard. So just because its on board does not mean you need no soundcard.

6. AGP market will dry up. Dont expect to be able to buy top notch graphic cards by the end of next year with AGP. The graphic companies cant support 2 typse of slots and they will go for PCIe for now.

7. Every PCI card that is in use shares its bandwidth with the other PCI cards. ISA card in use also needs time. So when you have 6 PCI cards that you really use that will give some load on your system. PCIe has individual lanes for each slot/channel on multi lane slots.

8. out of personal intrest... What PCI cards do you have that you have more than 4 excluding network?

9. One point none mentioned so far, the PCIe x16 slot is designed to deliver more current to the graphic card than AGP. Still not enough for the hottest Graphic cards, but more.

10. SLI motherboards for AMD have 1 to 3 PCI slots. Asus A8N Deluxe: 3 PCI slots. Intel nforce4 boards i heared are not working well yet.

11. Something else none mentioned, PCIe slots come in x1 x2 x4 x8 x16. While this sounds trivial it is not, because you can have "open ended" slots where you can plug in bigger cards and you can have slots that look like bigger slots but have less electrical contacts, so a PCIe x4 slot might actually only be a x2 slot, an x16 slot might only be x4 or x8. On SLI boards currently are 2 "x16" slots but electrical its only 1 x16 OR 2 x8.


So.. all in all... WHERE do you see the PCIe boards that have no PCI slots? There are some intel boards without pci slots i think... but none anyone would want.
If you want to go AGP to get 5 or 6 PCI slots then ok, do so. But dont start with wrong reasons for it.

[Overlag]

Originally posted by Schutt

2. All new AMD 939 that support "venice" core can also take the dual processor cpus that amd will bring out (AMD 64 x2).
 

nope! VIA's K8T890pro chipset DOESNT support X2 but does support venice... but then hardly ANY boards use it.

I cant understand why though.