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difference between pci and pci express

Posted: Fri Jan 07, 2005 10:12 am
by rshetts
Im looking to get a graphics card and bypass the integrated graphics on my mobo. I basically now little about this. I do not have an agp slot only pci. So whats the difference between pci and pci express and whats a good mid range card $150 price range? Thanks in advance for any advice!

Posted: Fri Jan 07, 2005 10:40 am
by SirReal
PCI-X requires a PCI-X motherboard.
If you only have a PCI slot, there's probably not a lot to be gained by buying a PCI card. Consider getting a new motherboard as well.

Re: difference between pci and pci express

Posted: Fri Jan 07, 2005 11:06 am
by RunningMn9
rshetts wrote:Im looking to get a graphics card and bypass the integrated graphics on my mobo. I basically now little about this. I do not have an agp slot only pci. So whats the difference between pci and pci express and whats a good mid range card $150 price range? Thanks in advance for any advice!
PCI is a shared bridging interface. Only one device can be driving data on it any one time, and if you have lots of devices fighting for contention - trouble.

PCI-Express is a point-to-point version of PCI. The graphics adapter and the CPU can talk to each other, and at the same time, the Hard drive and Memory could talk to each other.

Allegedly less contention and higher throughput (which is nice if you are pushing large quantities of data to let's say, a video card).

I've spent the last 9 years of my life writing device drivers for PCI adapters, but I'm not all that familiar with PCI Express (the first PCI-E project I will be working on is in the very early stages and I haven't gotten down to the details yet).

As the other poster said, you need a motherboard that supports PCI-E, and only the most recent (i.e. most expensive) video cards are available in PCI-E as far as I know.

Posted: Fri Jan 07, 2005 12:15 pm
by Daehawk
Seems like in the beginning price hehe..cause they are'nt really faster..or much.

Posted: Fri Jan 07, 2005 1:46 pm
by RunningMn9
Oh yeah. Another big difference. PCI is a parallel data interface, PCI-Express is not. It's serial, but it's hellafied fast serial transmission (serial transmissions can generally run much faster and over longer distances because you don't need to syncronize a parallel data stream).

The worth of moving depends on which PCI-Express you are using. There is PCI-Express x1/x4/x16 and ultimately x32.

Here's the throughput figures:

PCI-33 (your standard 33MHz PCI Bus): 133MBps
PCI-E 1x - 250 MBps
PCI-E 4x - 1000 MBps
PCI-E 16x - 4000 MBps

I *think* that currently motherboards are using PCI-E 16x to replace the AGP slot. AGP 8x has a throughput of 2133 MBps.

So, in theory, PCI-E 16x can pump nearly twice the same amount of data in the same amount of time. Or I guess it could pump the same amount of data in almost half the time.

That seems like something that would help in the graphics card department.

No one thought AGP was this shizzle when it first came out either.

Posted: Sun Jan 09, 2005 8:55 am
by rshetts
Thanks for all the info, looks like its time for a new MOBO!

Posted: Sun Jan 09, 2005 1:19 pm
by Freezer-TPF-
If you get a PCI-E motherboard, then the video card to look for is the 6600GT. The native PCI-E version is an awesome card for under $200.