DIGIT-ARC read-only archive · snapshot: July 23, 2026

I want to know PCI express slots are different from PCI

16 posts · originally from https://geek.digit.in/community/threads/i-want-to-know-pci-express-slots-are-different-from-pci.24965/

N
nawaz123 Original post #1
Mar 6, 2006 at 10:49 AM
I would like to know what is the difference in PCI express slots compare pci slots. Do not confuse with graphics pci express slots. Forget about PCI express slots for graphics. I know about that one. I Just want to know PCI express slots are small or they look same??. Becos if I upgrade my motherbaord with pci express slots. Can I connect my mercury tvtunercard which is having pci slot??
H
Mar 6, 2006 at 3:10 PM
hmm.....

there is a huge difference between pci n pci e slots.its like comparing ambassdor to mercedes.they look like same in colour.
abhishek_sharma
Mar 6, 2006 at 6:17 PM
yes pci express slots can be used to add ordinary pci cards...i.e. theyre backward compatible
D
Mar 6, 2006 at 9:29 PM
Not at all. Forget being compatible, the card won't even fit into the slot.
P
priyadarshi #5
Mar 8, 2006 at 9:15 PM
i've to buy a new motherboard for my P4 i'd also like to know about the differences and also which motherboard have the PCI express slots in them. Gigabyte's 915 or Intel's original 915? But here abhishek_sharma says theyre backward compatible whereas drvarunmehta says that the card won't even fit into the slot. Its totally confusing.
KHUBBU
KHUBBU #6
Mar 8, 2006 at 10:29 PM
wikipedia link on pci express:
*en.wikipedia.org/wiki/Pci_express

even better and comprehensive article:
*arstechnica.com/articles/paedia/hardware/pcie.ars

hope it clears ur confusion.
D
Mar 8, 2006 at 10:49 PM
*upload.wikimedia.org/wikipedia/en/thumb/f/fc/PCIExpress.jpg/250px-PCIExpress.jpg

You can see 5 slots in this photo.

1 & 3 are PCI Express x1
2 & 4 are PCI Express x16
5 is PCI

As you can see, the dimensions of all are greatly different. So how would a card meant for one slot, fit into another?
T
Mar 8, 2006 at 10:58 PM
ya exactly as drvarunmehta
said
the card won't even fit into the slot

i think it is clear as the above picture mentions.............
P
priyadarshi #9
Mar 9, 2006 at 12:27 PM
thank you all friends. your replies helped a lot. KHUBBU's link and drvarunmehta's picture made the scene clear. now i'd like to know about your suggestion on the best Intel's 915 (Chipset & Original) mobo having both PCI express slots and PCI normal slots in them of course with an option of AGP slot for my P4.
::vicky::
::vicky:: #10
Mar 9, 2006 at 8:52 PM
what is "X" in this
abhishek_sharma
Mar 9, 2006 at 9:39 PM
sorry guys i confused pcie with pci-x...

btw @ ::vicky::

A connection between a PCIe device and the system is known as a "link" and this link is built around a dedicated, bi-directional, serial (1-bit), point-to-point connection known as a "lane". A lane is capable of simultaneously transferring 250 MB/s of data in each direction. A link can use more than one lane at a time but all links compliant with the PCIe specification must minimally support single-lane connections, referred to as "x1" (pronounced "by-one") links.

For higher potential bandwidth, PCIe devices and systems can optionally support links using multiple simultaneous lanes – for example, a "x16" link uses 16 lanes. To support extra lanes, a PCIe card and slot must be designed to accommodate the extra electrical lines required (2 lines per lane). Card and slot types exist for x1, x4, x8, and x16 links

however, these are down plugging compatible...i.e. if u can add a x8 card to a x16 slot but a x16 card will not fit into a x1,x4,x8 slot...
that is actually clear frm the images posted earlier.
N
nawaz123 #12
Mar 10, 2006 at 11:41 PM
drvarunmehta said:
*upload.wikimedia.org/wikipedia/en/thumb/f/fc/PCIExpress.jpg/250px-PCIExpress.jpg

You can see 5 slots in this photo.

1 & 3 are PCI Express x1
2 & 4 are PCI Express x16
5 is PCI

As you can see, the dimensions of all are greatly different. So how would a card meant for one slot, fit into another?

At last u cleared my doubt..

PICTURE SPEAK THOUSAND WORDS THAN anything..
::vicky::
::vicky:: #13
Mar 11, 2006 at 3:01 AM
thanks abishek
D
Mar 11, 2006 at 9:16 AM
abhishek_sharma said:
yes pci express slots can be used to add ordinary pci cards...i.e. theyre backward compatible


hey mate PCI Express slots are not backward compatible.............
bcoz the voltage ratings of both are different.................
i have got it confirmed from Nvidia authorised service center...............
so mate please first do search about wat u r saying.............
rockthegod
Mar 11, 2006 at 11:54 AM
Hi drvarunmehta, what motherboard is that ? (frm which the pic is taken).. looks like an SLI mobo....
D
Mar 11, 2006 at 12:08 PM
Yes its an SLI mobo. Since it's yellow coloured I guess it's DFI.