HDMI only supports up to 60 Hz. It does support 120 Hz when transmitting 3D video, but AFAIK there's no way to hack that to work for regular video. If you want to do 120/144 Hz, you need displayport (or dual-link DVI, but I've never seen that on a laptop). This was one of the reasons I had a really hard time deciding between the P34W (only HDMI) and P35W (which has displayport). All Nvidia Optimus laptops use the integrated Intel video card to drive the screen. The nvidia GPU acts as a co-processor, and the image it generates is sent to the Intel card for display (you may have noticed there is no tearing - essentially, vsync is always on with this arrangement as only completed frames are sent from the nvidia to Intel card). A few laptops allow you to turn off this arrangement in the BIOS, leaving the nvidia card to drive the screen directly (at the cost of battery life). And even fewer laptops have probably the best arrangement - Intel card drives the screen, but nvidia card drives the HDMI port if you have an external monitor connected. But from the tests I've done, the Intel card is always in control of the P34W's video output, both internally and externally. A side effect of this arrangement is that certain old or poorly-coded games will only run on the Intel video card. These games were programmed to look for a video card, but assume you only ever have one video card so stop searching after finding one. So on Optimus laptops they find the Intel card and use it, instead of searching further, noticing the nvidia coprocessor GPU, and using that.