17 R5, AW3418DW, connections, G-Sync

Question

I currently own an Alienware 17 R5 laptop with the  GeForce GTX 1070 which has a few different outputs; mDP, HDMI, and USB-C. I've read that in order to utilize G-Sync, I need to connect my AW3418DW using the DP port and not HDMI. My 17 R5 has a mDP port. I'm looking into purchasing the Alienware AW3418DW monitor which has a DP in port. The  AW3418DW supports a resolution of WQHD 3440x1440p, 4ms 120Hz (OC) Refresh Rate. Can I connect this AW3418DW to my 17 R5 using a mDP to DP cable or an adapter and still maintain the 3440x1440p resolution? And will I be able to utilize G-Sync?

jphughan · Answer

Yes, you can use an mDP to DP cable to connect that display to your system. Technically you could also use an adapter plus a cable, but I'd recommend going with a cable simply because it's simpler, and especially when you're pushing high-bandwidth signals like 3440x1440 at a high refresh rate, simpler means less potential for problems.

In terms of G-Sync, as long as the mDP output is wired directly to the NVIDIA GPU rather than being wired to the Intel GPU with the NVIDIA GPU operating through Optimus, then yes you'll be able to use G-Sync. And according to a post from Alienware in this thread, the mDP output on the Alienware 17 R5 is indeed wired to the NVIDIA GPU without Optimus being involved, so as long as that's correct, you'll be good to go. According to that same thread, the USB-C output is wired to the Intel GPU, which would prevent G-Sync from being used through that output even though USB-C provides a DisplayPort signal. And as for the HDMI output, it doesn't have enough bandwidth for 3440x1440 at 120 Hz (the AW3418DW's manual says it only accepts 3440x1440 up to 50 Hz over HDMI), and as you already found, G-Sync doesn't ever work over HDMI at all anyway -- so mDP is definitely the way to go. Just make sure you actually go into NVIDIA Control Panel to enable G-Sync and set the refresh rate to max, because Windows defaults to 60 Hz, and the refresh rate configured in Windows is treated as the max allowed refresh rate even when G-Sync is enabled.

Lastly, it appears that using 120 Hz requires you to manually enable some sort of overclock feature in the AW3418DW's menu, otherwise you're limited to 100 Hz. So make sure you do that as well if you want that. However, the manual notes that enabling overclock modes can cause screen flickering.