Question Why would HDMI to DP adapters only work when card is in 2nd PCIe slot?

[rgmtek]

Weirdest thing. Been running 4 monitors for a few years on a gtx 750 no problem. I've never gamed once. I only use my video card for faster rendering with Premiere and only use my 4 monitors for workspace and never push them hard.

Anyway, just swapped out gtx 750 for gtx 1660. After swapping, I read somewhere that I'd had the 750 installed in the "wrong" (second furthest from the CPU) PCIe slot this whole time.

Everything was working perfectly with the 1660 in the 2nd slot (4 monitors using 1 dp cable to dp monitor and 3 hdmi to displayport adapters). Since I still had my case open though, I decided to take it back out and install it in the "correct" (closest to the CPU) PCIe slot. Couldn't hurt I thought.

Upon powering back up, I couldn't get the 1660 to detect the 2 monitors using the adapters no matter what I tried. I tried switching cables around, unplugging the cables, unplugging the power, to make sure it was the adapters that were the problem and sure enough that was it.

Updated drivers, uninstalled, reinstalled, everything. No luck. I finally gave up and switched it back to the "wrong" slot, powered back up and voila! Everything worked again no problem.

Designare Z390

th;dr: Why wouldn't adapters work on PCIe slot 1, but work perfectly on slot 2?

 

[Ralston18]

"I read somewhere that I'd had the 750 installed in the "wrong" (second furthest from the CPU) PCIe slot this whole time."

Source - "somewhere". Could be in error there.

Also: Any BIOS settings/configurations in play?

E.g.:

https://itstillworks.com/13409472/how-to-turn-on-a-pci-slot-in-bios

 

[rgmtek]

Haha "somewhere" was in the gigabyte gtx manual (after I installed it of course), then in the designare manual when the "correct" slot didn't work, then online in a few places when troubleshooting. I've never cared about maximizing performance for gaming so PCIe slot placement had never occurred to me and everything always worked so why read the manual? lol

Incidentally, I was following the other principle of spacing out components to maximize airflow, etc. I also have a huge noctua cooler with 2 fans over my CPU so installing my card there takes a little cramming. Plus everything worked fine so never thought about it.

Thanks for the answer. I'll check out the bios settings a little later.

I read "somewhere" online that the 1660 wouldn't typically access more than 8 lanes unless you were pushing it hard or overclocking, etc.

I'd also at some point like to install a PCIe SSD. I feel like it rather use the x16 slot for that.

Total noob with PCIe specifics so thanks for any help. I come from the old "if it fits there, it goes there" school but definitely trying to learn more.