What is VRAM?
One of the hardest differences in computers to explain is the video cards. A lot of companies will expound the virtues of “xyz” video card as a selling point for higher end computers. In reality, this part is not really ever going to be a concern to most average users. I often see the graphics card under-discussed in the realm of portable gaming and sometimes see customers saddled with a laptop that fails to deliver the needed performance after more than a few months in spite of otherwise powerful specifications.
As a gamer myself, this is a significant concern. As an Apple Specialist, the need to be able to explain these systems is doubly important. So I’ve had to develop an explanation that cuts through the technical jargon (the frames per second, the clipping, the refresh rates) and effectively presents how things work for the average user.
The two main things most computer users need to be aware of when shopping for graphics cards are integrated vs dedicated, and the amount of Video Memory (VRAM) the card provides. We’ll start with the VRAM.
Simply put, the more VRAM the better the performance. Typical amounts you find on cards today are 256MB and 512MB. Some extremely high end cards are hitting the gigabytes, but most are too expensive to worry about for the average user. Basically this number determines how much video data your computer can process at one time. Think of it as short term memory, but for graphics information only. When you run through a lush video game jungle, or load a large raw video file for editing, all of that data is being held in your computers VRAM. The more VRAM, the larger the video you can edit, with more special effects, or the more of a video game world can be rendered in sharp detail. Incidentally, as I write this, 256MB is plenty for most games and video processing. More than that is only necessary if you are doing pro studio level work, or running the absolute newest games with all of the graphics settings turned all the way up.
Now, comparing the amount of VRAM on two cards is easy. Look at the numbers and pick the higher one. But how do you compare an integrated graphics card such as the Nvidia 9400M found in current MacBooks and entry level iMacs, to a dedicated graphics card like the ATI 2600 Pro found in last years high end imacs. Both of these graphics cards claim 256MB of VRAM, so what sort of difference does integrated vs dedicated make? Here’s the analogy I’ve come up with to explain the way these two systems work. It is in the context of running a store because, well, that’s where I came up with it.
Imagine that you have a group of five people running a retail store. All of them are first and foremost out there on the floor helping customers. At some point during the day you receive a shipment of new product. Now someone has to be pulled off of the floor to unpack the new stuff. If you almost always have more people than you need to help all the customers, this is not a problem. But, if there are enough customers to keep all five employees busy, now your unpacking has ground to a halt. At best, you will be able to trickle new product onto the floor in small chunks, but you will most likely fall behind.
Now imagine the same store, but now you have a sixth employee whose only job is to unpack and receive new product. Most of the time, he’s probably sitting around not doing much. But, no matter how busy it gets on the floor, he’s still there, ready to unpack the new shipments. This employee is like dedicated VRAM.
Basically, an integrated card has to borrow resources from the computer up to a maximum of the specified VRAM. If the system can’t spare those resources, then your video work is going to be slow. Super slow. But with dedicated graphics cards, you can tax your system that little bit more, and still get some passable gaming/video performance.
Really what all this means is that if you are the kind of person who doesn’t play 3D games (or doesn’t play them much) and doesn’t do lots of pro level video editing, then when you buy a computer with a dedicated graphics card, you are paying extra for a resource you are just not going to be using 99% of the time. Integrated cards like the Nvidia 9400M have come so far that they are more than up to the tasks of the average user, and do a phenomenal job even with most games. You just don’t want to be running a thousand and one apps in the background or you will be pulling more of that system memory away from the game (like creating a rush of customers after sending someone to unpack).