PCIe to PCI-X bridge card

[Luke Maslen]

Hi Paul,

If the main chip on the PCI-X to PCIe bridge card is working well, then there should be enough speed for use with the Multibridge PCIe models. The last chips we tested were not working as well as expected and the supplier of those chips is working on the issues now which should help with any speed issues.

PCI-X is really very fast and there are several speeds of PCIe, ie 1 lane, 4 lane, 8 lane and 16 lane. We only need to use a 4 lane slot in HD or a 1 lane slot for SD. The DeckLink Extreme PCIe card is an example of a 1 lane card which is perfectly capable of uncompressed, 10-bit SD video.

I’m not a hardware engineer and don’t know if there would be any performance drop bridging from PCIe to PCI-X. However we’re only bridging to 4 lane PCIe so the PCI-X slots of current G5’s should be plenty fast enough for this purpose.

PCIe is not necessarily faster than PCI-X. The main reason why motherboard manufacturers have moved to PCIe is that PCIe motherboards have a lower cost of manufacture which in turn means that the price of computers can be made lower and therefore more competitive. Every technology has its pros and cons but the reason we are using PCIe is because the PCIe standard allows for an external connector. This contrasts with PCI and PCI-X where a card must be installed inside the computer and this is a problem if we want to add a lot of connectors on to the output of a card. With PCIe, we have an adapter card which is analogous to an extension lead which takes the PCIe slot outside of the computer. That means that the Multibridge Extreme can effectively plug straight in to the PCIe bus on the motherboard which is great for high speed work with video.

Regards,

Luke Maslen
Blackmagic Design