Are PCIe 2.0 and PCIe 3.0 backwards compitable?
- Thread starter Vermin
- Start date
According to one company their eventual PCI-E 3.0 models will be!
Q6: Will PCIe 3.0 products be compatible with existing PCIe 1.x and PCIe 2.0 products?
A6: PCI-SIG is proud of its long heritage of developing compatible architectures, and its members have consistently produced compatible and interoperable products. In keeping with this tradition, PCIe 3.0 will be fully compatible with prior generations of this technology, from software to clocking architecture to mechanical interfaces. That is to say PCIe 1.x and 2.0 cards will seamlessly plug into PCIe 3.0-capable slots and operate at their highest performance levels. Similarly, all PCIe 3.0 cards will plug into PCIe 1.x- and PCIe 2.0-capable slots and operate at the highest performance levels supported by those configurations.
http://www.pcisig.com/news_room/faqs/pcie3.0_faq/
Q6: Will PCIe 3.0 products be compatible with existing PCIe 1.x and PCIe 2.0 products?
A6: PCI-SIG is proud of its long heritage of developing compatible architectures, and its members have consistently produced compatible and interoperable products. In keeping with this tradition, PCIe 3.0 will be fully compatible with prior generations of this technology, from software to clocking architecture to mechanical interfaces. That is to say PCIe 1.x and 2.0 cards will seamlessly plug into PCIe 3.0-capable slots and operate at their highest performance levels. Similarly, all PCIe 3.0 cards will plug into PCIe 1.x- and PCIe 2.0-capable slots and operate at the highest performance levels supported by those configurations.
http://www.pcisig.com/news_room/faqs/pcie3.0_faq/
Geoff
VIP Member
Are you sure you don't mean is PCI-E 2.0 backwards compatible with PCI-E 1.1?
"In some rare cases it is possible that a PCI-E 2.0 card will not work correctly on a PCI-E 1.0a slot. This is only limited to certain video cards." http://en.wikipedia.org/wiki/PCI_Express
" However, a device designed to operate specifically at 5GT/s must also support 2.5GT/s signaling. The PCIe Base specification covers chip-to-chip topologies on the system board. For I/O extensibility across PCIe connectors, the Card Electromechanical (CEM) and ExpressModule™ specifications will also need to be updated, but this work will not impact mechanical compatibility of the slots, cards or modules." http://www.pcisig.com/news_room/faqs/pcie2.0_faq/
You forgot the exceptions.
hermeslyre
VIP Member
The wiki was in the shits about this, people were editing it implying full incompatibility. I had to jump in there with the above assertion. I was only actually able to find one or two 1.0a motherboards that sported the incompatibility though, one was a biostar.
To be fair, I believe you took the rare exception for the rule.
Besides the few exceptions the main difference is in what the board itself supports rather then seeing a totally different type of PCI-E slot. Plus there's a slight different mainly in the bios between 1.1 and 1.0a seen. The newer cards will see a far better backward capability with those however making those a little more universal.
Geoff
VIP Member
Yes thats true, but all recent PCI-E motherboards use the 1.1 standard.
There were only a few 1.0a boards that had a problem and I think most of those were fixed with a bios update. I,ve installed quite a few even on older 939 boards and never had a problem. So to say that a 2.0 card requires a 2.0 slot is way overstated and untrue.
http://www.pcisig.com/news_room/faqs/pcie2.0_faq/
Q5: Then PCIe 2.0 must be backward compatible with PCIe 1.1 and 1.0?
A5: Yes. The PCIe Base 2.0 specification supports both the 2.5GT/s and 5GT/s signaling technologies. A device designed to the PCIe Base 2.0 specification may support 2.5GT/s, 5GT/s or both. However, a device designed to operate specifically at 5GT/s must also support 2.5GT/s signaling. The PCIe Base specification covers chip-to-chip topologies on the system board. For I/O extensibility across PCIe connectors, the Card Electromechanical (CEM) and ExpressModule™ specifications will also need to be updated, but this work will not impact mechanical compatibility of the slots, cards or modules. Currently, the PCI-SIG is defining the PCIe CEM 2.0 specification which has been released to members for review at v0.5. There are currently no plans to adapt the PCIe Mini CEM specification for the faster bit rate as the market need has not yet materialized.
http://www.pcisig.com/news_room/faqs/pcie2.0_faq/
Q5: Then PCIe 2.0 must be backward compatible with PCIe 1.1 and 1.0?
A5: Yes. The PCIe Base 2.0 specification supports both the 2.5GT/s and 5GT/s signaling technologies. A device designed to the PCIe Base 2.0 specification may support 2.5GT/s, 5GT/s or both. However, a device designed to operate specifically at 5GT/s must also support 2.5GT/s signaling. The PCIe Base specification covers chip-to-chip topologies on the system board. For I/O extensibility across PCIe connectors, the Card Electromechanical (CEM) and ExpressModule™ specifications will also need to be updated, but this work will not impact mechanical compatibility of the slots, cards or modules. Currently, the PCI-SIG is defining the PCIe CEM 2.0 specification which has been released to members for review at v0.5. There are currently no plans to adapt the PCIe Mini CEM specification for the faster bit rate as the market need has not yet materialized.
[-0MEGA-];916770 said:
The early PCI-E 16x slots were the ones seeing the 1.0a there not the boards that followed for the most part. Even the 939 board in the last here saw a 1.1 slot there. Pretty now everything is standardized like seen with the older AGP 2x/4x boards accepting a new 4x/8x model card like the HD 2600Pro.
The problem will be for those still running one of the losing model boards and wondering why the latest cards won't run correctly. Then they're stuck either going for a bios update hoping that will work or replacing an antiquated board?
