NVIDIA Optimus - Truly Seamless Switchable Graphics and ASUS UL50Vf

ASUS UL50Vf Overview

The ASUS UL50Vf is essentially the Optimus version of the UL50Vt, and the UL50Vt is the 15.6" version of the UL80Vt we liked so much. To be honest, we are a lot more interested in the ASUS UL30Jc—a 13.3" Optimus CULV laptop with an optical drive (some models will even ship with Blu-ray support in the near future). Here are the specifications for the UL50Vf.

Obviously, there were some changes to the motherboard in order to work with Optimus. Specifically, ASUS was able to remove any multiplexers and extra signal routing from the UL50Vt design. However, those changes are on the inside and you can't see any difference looking at the exterior. Specifications remain the same as the UL50Vt/UL80Vt, and performance is virtually the same as the UL80Vt we tested. (There will be some minor differences due to the change in LCD size and the use of different drivers, but that's about it.)

Pretty much everything we had to say about the UL80Vt applies to the UL50Vf. The features are great, and Optimus makes it even better. You can overclock the CPU by 33% in order to improve performance, or you can run the CULV processor at the stock speed and improve battery life. Unlike Optimus, changing the CPU speed doesn't happen on-the-fly (unfortunately), but it is a little easier than what we experienced with UL80Vt. This time, instead of requiring a full system reboot, enabling/disabling Turbo33 only requires the system to enter suspend mode. In that sense, Turbo33 is sort of like switchable graphics gen2: it requires manual user intervention and takes 10 to 15 seconds to shift modes. Ideally, we would like to be able to switch the overclock without suspending, and even better would be the option to enable overclocking on AC power and disable it on DC power.

The UL50Vf carries over the aluminum cover on the LCD lid along with the glossy interior plastic and LCD. It also uses the same 1366x768 LCD resolution. Considering the larger chassis, we feel ASUS would have been better off increasing the LCD resolution slightly (1440x900 or 1600x900 would have been good), and we would have also appreciated a faster dGPU. With Optimus allowing the GPU to switch on/off as needed and a 15.6" chassis, we feel ASUS should have been able to get something like the GT 335/325M into the UL50Vf. After all, Alienware is managing to cram similar hardware into an 11.6" chassis with the M11x!

Before we get to the tests, we did encounter a few minor glitches during testing. First, we couldn't get x264 decode acceleration to work with the dGPU using Media Player Classic - Home Cinema. We could set the application to load on the discrete graphics, but MPC-HC apparently didn't know how to talk to the Optimus GPU and ended up running off the IGP. Since the GMA 4500MHD was more than capable of handling our 720p and 1080p x264 files, we're not too concerned with this issue. Another glitch is that CPU-Z refused to work; it would hang at the graphics detection stage. This isn't so much a problem with Optimus as a need for changes to CPU-Z—and very likely some other low-level tools that talk directly to the graphics hardware. (We didn't try any overclocking or tweaking of the GPU on the UL50Vf, but we suspect it might be a bit trickier than normal.)

Finally, when using the dGPU and playing games, we periodically noticed a slight glitch where the screen would flicker black for a frame. We couldn't come up with any repeatable test, but it seems like the problem may be related to the Copy Engine transferring incorrect data. This was not limited to any one title, but it occurred most frequently during our Empire: Total War testing (usually at least once every 60 seconds). It would hardly be surprising to find that there are a few bugs in the NVIDIA drivers, and most likely this is one of them. We didn't find the occasional "flicker" to be a serious issue and at present we really don't have enough information to say more about what might be causing the glitch we experienced. We'll do some additional testing to see if we can determine if this is more of a problem with specific games or if it happens on all games.

We've run an abbreviated set of tests with the UL50Vf. As mentioned, performance is virtually identical to the UL80Vt, the primary difference being the ability to immediately switch between discrete and integrated graphics as necessary. We will highlight both the old UL80Vt and the UL50Vf in our charts for comparison; you can see additional performance results for the UL80Vt in our previous review. All tests were conducted with the default graphics settings, so the discrete GPU is used when Optimus deems it beneficial and the IGP is used in all other cases. The gaming and general performance tests are run with Turbo33 engaged (33% CPU overclock) while battery testing was conducted at stock CPU speed.