I thought I'd spend some time on a new Lenovo technology feature, one we call Switchable Graphics. One of the fundamental choices facing a notebook buyer is what type of graphics subsystem to buy. While there are many different types, the choice can fundamentally be broken down to "Integrated" or "Discrete." Integrated graphics are the graphics capabilities that come built in the chipset.
- Advantages: Low cost. They are already built in for "free" as part of the rest of the package. Less power consumption (more on that later.)
- Disadvantages: "Shared" graphics memory, which means you lose some main system memory to graphics. Also, the graphics capabilities of integrated graphics chips decidedly lag those of discrete graphics chips.
Discrete graphics are graphics provided by an external graphics chip, usually by nVIDIA or ATI. These have their own dedicated graphics memory which frees up main system memory for other tasks.
- Advantages: Much faster performance. More capabilities for things like hardware accelerated high definition playback. (Yes I know Montevina integrated graphics supposedly has this capability, but Intel has yet to satisfactorily deliver on that promise)
- Disadvantages: More costly and much more power consumption, which results in less battery life.
On a desktop, the answer is usually simple. If you care about performance, choose a discrete graphics card and don't worry about it any longer. On a mobile PC, the answer is not quite as cut and dried. The reason is that there are major tradeoffs in battery life with each choice. Longtime readers of this blog will recall that I've always eschewed discrete graphics on my notebooks because they draw significant amounts of power. When you use a discrete graphics chip, you lose an hour or more of use per battery charge. To say this is a huge loss is severely understating the problem. Most users don't need this kind of power at all. The integrated graphics chip has more than enough oomph to run Windows, email, web browsing, etc. The rest is wasted as heat and lost productivity due to less system runtime. That said, there are still a significant number of people that buy discrete graphics because of a single application, or "just in case." They simply just suffer the gains with the losses. Enter Switchable Graphics. A Switchable Graphics machine has BOTH an integrated and a discrete graphics chip built into the system. That way there is computing power when you need it and power savings when you don't. The idea isn't new. Sony introduced this technology several years ago on one of its ultraportables. However, that implementation had a major drawback. In order to change from integrated to discrete graphics mode, the user had to completely reboot the system – rendering it practically useless. Lenovo's implementation is different. We worked with ATI and Intel to develop a system where the user could dynamically swap over from one graphics subsystem to another without having to reboot his/her system. By simply clicking our battery gauge on ThinkPad Power Manager, a user can switch from integrated to discrete modes with 2 – 4 seconds. Though there is a warning that some applications fuss when going from graphics mode to graphics mode, in practical use, most of them behave just fine.
This is one of the primary reasons we switched from nVIDIA graphics back to ATI graphics on our ThinkPad Montevina products. nVIDIA just didn't have this technology available. (See below for edit notes) Using switchable graphics allows a user to have the best of both worlds – power savings plus power when you need it. Many people who use this technology set it to run on discrete graphics when plugged into electricity and on integrated graphics while mobile. The major drawback is that this technology uses architectural improvements in Windows Vista to do its magic and will not work with XP systems. There have been many requests to make this so, and the team is studying whether this would be feasible in a future release. For those of you running XP, you still have a choice. In BIOS, there is a setting for the graphics subsystem that allows you to choose to run in either integrated or discrete mode. You would have to reboot and go into BIOS to change your preference, but could still switch on an occasional basis. For me, I'm going to set my next machine BIOS to "integrated" and just leave it there – regardless of what operating system I'm running. You automatically get switchable graphics capabilities when you choose one of our Montevina systems with an ATI graphics chip. These include the ThinkPad T400, T500, R400, and W500. The one exception is the R500 with ATI graphics. Lenovo did not build this capability into that system. EDITED BY MATT KOHUT ON 8/30/08 I owe nVIDIA an apology. The strikethrough text at the top was what I thought was correct information, but I was wrong. nVIDIA does have switchable graphics technology available which announced in July on a Sony laptop with more vendors to announce later. Their name for this technology is "Hybrid Graphics." According to nVIDIA this is also a Vista only solution at this time.