FreeSync: AMD's Approach To Variable Refresh Rates

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AMD's FreeSync technology is gaining momentum, but is the buzz warranted? We did our own research, worked with Acer and spoke with AMD to find out.

Followup With Acer

Here are a few follow-up questions I asked Acer, along with responses from the company:

TH: What is the chip model of the Realtek/Novatek/MStar/(other?) scaler in the display?

Acer: We don't provide this information, for competitive reasons.

(Ed.: Next time, I'll make a mental note to open up the display and look before sending it back. Unfortunately, the display had been shipped back at the time we received this answer)

TH: Can you confirm the FreeSync range of the display?

Acer: The FreeSync range is 40 to 144Hz.

TH: Can you confirm that the display does not support backlight strobing?

Acer: It does not support backlight strobing.

TH: Is there any visual way to confirm that FreeSync is operating, other than just trusting that the option is checked in the Catalyst control center?

Acer: You can run the AMD FreeSync demo.

TH: Can you confirm that the overdrive setting is disabled in FreeSync mode (or, apparently, when using a DisplayPort cable in general with a GPU that supports FreeSync), whether that feature is enabled? I understand there should be a firmware update to address this issue. Does the display we used already include the latest firmware with the overdrive/FreeSync fix?

Acer: Users can adjust the OD setting in FreeSync mode. They can select Extreme/Normal/Off manually. The OD implementation is based on the scaler. AMD and our Original Device Manufacturer aligned response time values in FreeSync mode and implemented into the scaler design. AMD checked every Freesync monitor and worked with our product group during project development. We also went through AMD certification.

(Ed.: This is only true with the latest firmware installed. With the stock firmware, overdrive is effectively disabled when a DisplayPort connection is used, regardless of whether FreeSync is enabled or not)

Filippo L. Scognamiglio Pasini
31 Comments Comment from the forums
  • hatib
    more expensive but gr8 nvidia gsync i like it
    Reply
  • DbD2
    Imo freesync has 2 advantages over gsync:
    1) price. No additional hardware required makes it relatively cheap. Gsync does cost substantially more.

    2) ease of implementation. It is very easy for a monitor maker to do the basics and slap a freesync sticker on a monitor. Gsync is obviously harder to add.

    However it also has 2 major disadvantages:
    1) Quality. There is no required level of quality for freesync other then it can do some variable refresh. No min/max range, no anti-ghosting. No guarantees of behaviour outside of variable refresh range. It's very much buyer beware - most freesync displays have problems. This is very different to gsync which has a requirement for a high level of quality - you can buy any gsync display and know it will work well.

    2) Market share. There are a lot less freesync enabled machines out there then gsync. Not only does nvidia have most of the market but most nvidia graphics cards support gsync. Only a few of the newest radeon cards support freesync, and sales of those cards have been weak. In addition the high end where you are most likely to get people spending extra on fancy monitors is dominated by nvidia, as is the whole gaming laptop market. Basically there are too few potential sales for freesync for it to really take off, unless nvidia or perhaps Intel decide to support it.
    Reply
  • InvalidError
    It sounds hilarious to me how some companies and representatives refuse to disclose certain details "for competitive reasons" when said details are either part of a standard that anyone interested in for whatever reason can get a copy of if they are willing to pay the ticket price, or can easily be determined by simply popping the cover on the physical product.
    Reply
  • xenol
    I still think the concept of V-Sync must die because there's no real reason for it to exist any more. There are no displays that require precise timing that need V-Syncing to begin with. The only timing that should exist is the limit of the display itself to transition to another pixel.

    It sounds hilarious to me how some companies and representatives refuse to disclose certain details "for competitive reasons" when said details are either part of a standard that anyone interested in for whatever reason can get a copy of if they are willing to pay the ticket price, or can easily be determined by simply popping the cover on the physical product.
    Especially if it's supposedly an "open" standard.
    Reply
  • nukemaster
    It sounds hilarious to me how some companies and representatives refuse to disclose certain details "for competitive reasons" when said details are either part of a standard that anyone interested in for whatever reason can get a copy of if they are willing to pay the ticket price, or can easily be determined by simply popping the cover on the physical product.
    It was kind of the highlight of the article.

    (Ed.: Next time, I'll make a mental note to open up the display and look before sending it back. Unfortunately, the display had been shipped back at the time we received this answer)It is a shame that AMD is not pushing for some more standardization on these freesync enabled displays. A competition to ULMB would also be nice to see for games that already have steady frame rates.
    Reply
  • jkhoward
    Of course you think NVIDIA solution will win. You always do. This forum is becoming more and more bias.
    Reply
  • InvalidError
    16718305 said:
    I still think the concept of V-Sync must die because there's no real reason for it to exist any more.
    As stated in the article, modern LCDs still require some timing guarantees to drive pixels since the panel parameters to switch pixels from one brightness to another change depending on the time between refreshes. If you refresh the display at completely random intervals, you get random color errors due to fade, over-drive, under-drive, etc.

    While LCDs may not technically require vsync in the traditional CRT sense where it was directly related to an internal electromagnetic process, they still have operational limits on how quickly, slowly or regularly they need to be refreshed to produce predictable results.

    It would have been more technically correct to call those limits min/max frame times instead of variable refresh rates but at the end of the day, the relationship between the two is simply f=1/t, which makes them effectively interchangeable. Explaining things in terms of refresh rates is simply more intuitive for gamers since it is almost directly comparable to frames per second.
    Reply
  • Freesync will clearly win, as a $200 price difference isn't trivial for most of us.

    Even if my card was nVidia, I'd get a freesync monitor. I'd rather have the money and not have the variable refresh rate technology.
    Reply
  • dwatterworth
    A suggestion for the high end frame rate issue with FreeSync, turn on FRTC and set it's maximum rate to the top end of the monitors sync range.
    Reply
  • TechyInAZ
    Very interesting read. I never knew that variable refresh rates had effects on light strobing.

    I wonder how adaptive sync and G sync will work when the new OLED monitors start hitting the market?

    Reply