Lucid’s Virtu unites any and all GPUs
Posted by Robert Dow and Jon Peddie on March 8th 2011 | Discuss
Lucid (formally LucidLogix) came up with the idea for a PCIe sniffer that could intercept API calls, back in 2006. The company stayed in stealth mode, living on VC money and didn't actually show a product till 2008.
The original idea was that Lucid would build a chipset that would allow any two (or more) AIBs to operate together in a complimentary way – what AMD calls Crossfire, S3 calls Multi Chrome, and Nvidia calls SLI. However, Lucid promised to enable any of them, any combination of them, any generation or SKU of them, to run together and boost each other.
Lucid began talking publicly about the technology, which they named Hydra, in 2008, and coincidently (it really was) while Intel and Nvidia were haggling about who could and couldn't run SLI in the new Nehalem motherboards. Since we had known Lucid a long time we thought for sure they would be the solution to the stalemate, but for reasons that were never clear, that didn't happen. Nvidia and Intel worked out a compromise (put an nF100 on the mobo).
Then at CeBit 2010 Lucid demonstrated motherboards with their Hydra 200 chip. At last the technology was here. It got respectable but not rave reviews, and there were limited units to be tested so benchmarking had to be done at Lucid.
AIBs with brand X GPUs and Hydra were shown at Computex that could be put in a system with a brand Y GPU and get the same effect as if the Hydra chip was on the mobo. Powercolor built the AIB (with an AMD HD5770) (http://lucidlogix.com/whereto_buy_vga.html).
Lucid was deep into the core of core and knows as much about PCIe traffic as anyone. They developed clever sensing technology for PCIe bus behavior and traffic, and could easily go into the tools business.
So it was not difficult to accept their software concept of GPU virtualization software for 2nd generation Intel Core processor platforms, they are calling Virtu.
According to Lucid, with Virtu technology next-generation PCs will be able to dynamically balance the embedded media features of Intel's Core processor graphics with high-end, DirectX 11 3D, anti-aliasing and performance features of discrete GPUs, while reducing the power drain of traditional entertainment desktops. This, says Lucid, will provide the consumer optimal simultaneous performance in 3D gaming and video functions like transcoding and HD playback without the need to swap video cable connections between GPUs.
Lucid's software stack is illustrated in the following diagram
The purpose of Virtu is to enable the Sandy Bridge CPU to perform the tasks that it is best at i.e.: transcoding, while enabling hardcore 3D graphics applications to run off the AIB which enables SVB systems to run DX 11 apps while still taking advantage of SNB's best attributes.
We ran four tests to evaluate the software, SNB alone, SNB with its graphics put to sleep and an AIB installed, and SNB and AIB and Lucid's Virtu application manager.
The results were interesting, and are shown in the following charts
As the chart shows, running with the Lucid Virtu software drops the performance on one game (Stalker) while enhancing another (Starcraft). It makes sense that there should be some hit with Lucid's Virtu running, the difference with Stalker was -7.3% while Starcraft got a 10.4% improvement.
Additionally, drivers for EPG and AIB must be installed prior to Virtu installation. In the process of using Virtu, the monitor should be always connected to Sandy Bridge.
We also tested for video transcoding performance, something the SNB shines at, and did a Vantage test as well, as shown in the following chart.
To get things set up properly you have to enter the Bios, navigate to the Configuration tab scroll to Video and Change from "Enable if Primary" to "Always Enable".
What do we think?
Running the monitor through the Sandy Bridge EPG rather than the discreet AIB allows the shutdown of the AIB when it is not in use thereby saving power consumption, so it's a lot like Nvidia's Optimus or AMD's Switched Graphics in that sense.
Right now only motherboard manufacturers are offering Virtu. However, Lucid will soon be doing a free end user trial. The product price to OEMs is negligible to system cost.
Virtu is a good balance for getting the most out of all the processors one has in their system – it's a true heterogeneous processor maximize, and a great way to reduce power consumption when the performance is not called for.
Game enthusiasts will not be attracted to it because of the load-balancing overhead hit. But then game enthusiasts probably don't do much transcoding.
What Lucid needs to add is a simple on-off button so when max graphics performance is desired the BIOS and Virtu software is switched out, and vice-versa. The only problem that would leave: if the need to move the monitor's cable from the AIB to the SNB and vice-versa.
So as of now it's an all or nothing setup.