As it's the more mature technology, there's really no mystery here. G-Sync works and it works great if you have an Nvidia GPU. PCWorld's GPU reviewer Brad Chacos, for example, ran into a problem trying to get a Radeon R9 290X to work with an Acer 4K G-Sync panel and had to abandon it for a standard Dell 4K monitor to complete his testing of that card.
Firing up FreeSync
AMD's FreeSync isn't quite as easy, but it's by no stretch difficult: You need a compatible Radeon card or APU. While Nvidia's list of supported cards stretches pretty far back and deep, AMD's is very limited: The Radeon R9 295 X2, -290X, -290, -285; and the Radeon R7 260X or -260. That's it for discrete GPUs.
You'll also need a compatible driver to switch on the support. For my hands-on, I relied on a beta driver that AMD provided.
I used LG's wide-aspect 34-inch 34UM67 display. This is a 2560x1080 IPS panel with a maximum refresh of 75Hz. To turn on FreeSync, you go into the monitor's OSD, drill into the general settings tab, and flip it on.
Once that's done, you'll also need to make sure it's enabled in the control panel for your Radeon card. I failed on my first attempt, because the machine I used — a Core i7-5960X Haswlell-E rig with a pair of Radeon R9 290X cards — had CrossFireX enabled by default when I installed the new driver. Turning CrossFireX off allowed FreeSync to be switched on, but I lost the power of one GPU. Yup, there's no CrossFireX support — yet. Remember, it's a beta. An AMD official said to expect CFX capability with FreeSync next month. We'll see. Did I mention that G-Sync works fine in SLI?
My first test was AMD's own FreeSync demo. It's a windmill with the blades rotating and tearing was very apparent with both FreeSync and V-sync turned off. WIth V-sync turned on, I ran into stuttering that occurs due to the timing of how frames are rendered and pushed to the monitor being out of sync.
FreeSync isn't just about demos, so I also fired up the CodeMaster's Grid 2 driving game. I wanted an older game that would hit high frame rates and this two-year-old title set to medium quality didn't disappoint. Even on the wide-aspect 2560 x 1080 monitor I could hit in excess of 250 frames per second with V-sync switched off and FreeSync on. This excessive frame rate would normally exhibit tearing, but I didn't see any. Unfortunately, I didn't have an identical G-Sync rig and monitor nearby, so I could only rely on my memories of running 4K and G-Sync. But FreeSync seems to work pretty damned well.
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