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Lucidlogix Virtu Supports AMD; Intros Vsync

By - Source: Tom's Hardware UK | B 0 comment
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Virtu was a smash-hit because it enabled Quick Sync functionality on Z68-based motherboards with discrete graphics. There doesn't seem to be as much need for it on AMD's platforms. Yet, Lucidlogix is announcing support for AMD, notebooks, and all-in-ones.

I’ve spent a fair bit of time exploring Lucidlogix’s technology. First, I was less than blown away by Hydra in MSI Big Bang Fuzion: Pulling The Covers Off Of Lucid’s Hydra Tech. Then, I was hopeful about Virtu’s prospects in Can Lucidlogix Right Sandy Bridge’s Wrongs? Virtu, Previewed. Most recently, I was thoroughly impressed by Virtu in Intel Z68 Express Chipset Preview: SSD Caching And Quick Sync. Needless to say, I spent more time on the phone with Israel in the past six months than any other point in my life, combined. The last time we talked, Lucidlogix’s founder, Offir Remez, made me promise not to say anything about today’s announcement until the Computex launch, when it'd be ready.

And now it is. The company is introducing two separate technologies at this year’s show. One builds on technology already available; the other is newer, and will require a more in-depth look when it's ready for evaluation.

First, Virtu is being enabled not just on desktop H61-, H67-, and Z68-based motherboards, but also on certain Sandy Bridge-based notebooks and all-in-ones. Plus, the company says it’s extending Virtu support to Brazos-, Llano-, and Bulldozer-based platforms from AMD.

Of course, the Brazos platforms we’ve seen don’t have any integrated graphics features that’d necessitate simultaneous access to on-board and discrete GPUs, so the play here has to center on power. Presumably, we’ll someday see an AMD machine with integrated and add-in graphics. Virtu will let that platform output via the low-power implementation, allowing the meatier card to idle along. Instantiating a game in Virtu’s white list shifts rendering to the discrete adapter, yielding enthusiast-class performance. Extra power is consumed only when it’s needed.

I asked Lucidlogix’s Remez about the functionality there—isn’t Virtu supposed to be able to shut the discrete card down completely when it isn’t needed? Indeed, that’s the way the software is supposed to work; purportedly, it’s just a BIOS optimization that needs to be made on motherboards that license Virtu. We just haven't seen any board vendors enable the necessary change yet. Of course, notebooks that employ Virtu Universal are expected to include this capability, similar to Nvidia’s Optimus technology.

Getting back to AMD: unfortunately, the company’s Brazos APUs aren’t exactly great candidates for a relationship with discrete graphics. Moreover, Zambezi is the only Bulldozer-based processor expected near-term—and it isn’t an APU at all. Llano might have something to offer, but even then I suspect most true gamers will wait for Zambezi, leaving Llano to the folks who actually plan to use integrated graphics and not an add-in card. Thus, Virtu Universal remains great for Intel’s customers. For the time being, its relevance to AMD is iffy.

Within the new version of Virtu you’ll find another technology called Virtual Vsync. Lucidlogix’s goal here is to enable unbridled frame rates with v-sync turned on (rather than imposing a 60 FPS limit). The contention today is that enthusiasts are forced to choose: v-sync on with a frame rate cap or v-sync off and cope with tearing. Virtual Vsync purports to eliminate both compromises. Subjective testing will have to wait until we have a version of the software in-house. In the meantime, feel free to weigh in on Twitter if you personally see a use for a piece of software like Virtual Vsync.

According to Lucidlogix, it decouples the CPU/GPU/display from the refresh rate, allowing the rendering pipeline to operate as quickly as it can. From there, a threaded algorithm is applied to predict where a tear might occur. Based on this information, plus user input, the software makes sure there is no more than one frame of latency (versus two to three with v-sync enabled).

The relationship with Virtu is supposed to be symbiotic. As we learned in my Virtu preview (the second link up at the top of this story), when you're connected to the integrated output, Virtu is mapping the discrete card's frame buffer to the HD Graphics engine. Now, with Virtual Vsync, HD Graphics can signal back with the status of the screen refresh and its own memory space. With in-game v-sync enabled, you could have been facing two to three frames of latency with 16.6 ms per frame (1000 ms/s divided by 60 frames/s), totaling up to 50 ms. In a game that might have run at 100 FPS, Virtual Vsync, rendering one frame ahead, drops that to 10 ms total (1000 ms/s divided by 100 frames/s).

Now, the math adds up and sounds great. However, Offir knows that I'm a skeptic and have to see a technology in action to believe it. I had my gripes about Virtu, but Lucidlogix came back to me with a new build ahead of the Z68 launch that did what I was hoping to see. This time around, one of our men on the ground in Taipei, Tom's Hardware DE managing editor Ben Kraft, reports back that he perceived micro-stutter in the Virtual Vsync demo. So, the jury remains out on this one until the software is ready for testing our lab.

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