PCIe 3.0 is supposed to be backward compatible according to PCIe standards, but the only way to know for sure is by testing the card. Since the Wi-Fi card is installed and not working, it is possible that this is a compatibility issue. A BIOS update may help recognizing the card. What is your BIOS version? Also, let me know your operating system.
First of all, let's get it right. The P35 chipset used on the DP35DP board is compliant with the PCIe 1.1 specification. The tp-link TL-WN881ND is compliant with the PCIe 2.0 specification - and, according to its datasheet, is backwards-compatible with PCIe 1.1. This issue has absolutely nothing to do with PCIe 3.0.
I can think of three possibilities to investigate (in priority order): (1) something wrong with the card, (2) something wrong with the board or (3) a compatibility issue. I prioritize #1 because this is the easiest to investigate; you simply test the card in another PC. In regards to items #1 and #2, I point out that they are both very aged cards. The DP35DP is 9 chipset generations out of date and was manufactured 9+ years ago (manufacturing started in 2007). I could not find the same information for the TL-WN881ND but, considering that it supports Wireless-N technology, it has quite a few years under its belt as well (802.11n was ratified in 2009, but some cards supporting it were on the market well ahead of this ratification). In my opinion, all bets are off. Both are at or beyond the standard (7-year) MTBF for the components used on these boards and thus both have to be classified as being in the imminent-failure category. IMHO, both should be trashed and replaced with something more, um, modern.
Help this helps; sorry for the dose of reality...
Hello everyone, thank you for your feedback.
After updating the bios to the latest version available on Intel, and chech the setup pci in the Bios, the problem is not solved.
The card is new and works in a newer computer, so I assume that the PCIe 2.0 is not supported by the PCIe1.0 motherboard.
So I ordered another WIFI card PCI 32Bits 3.3v-5.0v , old but should work properly.
Amy , Yes sure !
here is the end of the problem,
I received the 32bits PCI card and it was directly recognized by the system, driver installed it works correctly.
I therefore deduce that the motherboard is simply too old compared to the recent PCIe card that I had bought.
Thank you for your help