Tuesday, December 21, 2010

(Assembled is a series in which The Indian Geek will be looking at how to choose the components for assembling your own home Desktop PC, over the course of a few weeks. This week's article is about choosing the GPU or graphics card)

GPU - From Wikimedia Commons

Today we’re going to share with you what we know about graphics cards and tell you what to look for when you’re buying one. First lets see what a graphics/video card is. In the 80s and 90s, a video card was merely a device that converted the digital signals that a computer used, into analogue signals that an old CRT monitor used. The CPU did all the calculation, including everything related to the content the monitor displayed. As computers developed and got faster, video cards were given the ability to do some of these calculations thereby reducing the load on the CPU. In the late 90s, the 3dfx Voodoo was the first successful 3D accelerator card that redefined gaming. As the technology developed, more and more work was taken off the CPU and onto the graphics card. Today’s graphics cards are small supercomputers in themselves. They have their own processor (Graphics Processing Unit, or GPU), video RAM, bus controller, BIOS, etc. They have become so fast and powerful that they are also used for pure mathematical applications that have nothing to do with graphics. In today’s world, almost all processor+chipset combinations from either AMD or Intel have an integrated graphics chipset; however, this is far far lower in capabilities, than a dedicated graphics card – which is what we’ll be looking at in this article.

So if you’re not going to play any games, do you really need a graphics accelerator card? In the days of Windows 95 and 98, or even XP, graphically, there was very little going on. We also used small monitors with low resolutions (800x600 or 1024x768). So as long as you don’t run any 3D intensive game or application, the CPU was more than capable of handling the load. But that’s not the story anymore. Nowadays everything has become so graphically intense, that an accelerator is a necessity. All the cool transparency and sliding effects in Windows 7’s Aero desktop is completely handled by the graphics accelerator. Further more, monitors are getting bigger and sharper. If you play a 1080p video, that’s 1920x1080 pixels being displayed at about 30 frames per second. That’s a total of 6,22,08,000 pixels a second! While today’s CPUs might be able to handle this, a GPU will do a far better job. The newer generation nVidia and Ati cards also do some of the video decoding, thereby reducing CPU load even further. A good example for this would be the nVidia Ion based Intel Atom computers. A tiny Atom processor just does not have the power to decode and play high resolution videos. But coupled with an nVidia Ion GPU, it can play 1080p video with ease. Thus even though nowadays all computers have some form of an integrated GPU in them, it is really worth taking the time to find a good dedicated graphics card.


nVidia GeForce logo ATi Radeon logo

So what makes a GPU different from a CPU? Why can’t we just get a faster CPU instead of a GPU? The main difference between them is a GPU’s ability to parallelly process large amounts of calculations all at once. While a CPU might have 1,2,3,4 or 6 cores, a GPU can have hundreds of cores or stream processors. While each core is much slower than a CPU core, the sheer number of them makes GPUs very powerful. You can view a video of the Mythbusters demonstrating this, at the nVidia website, here.

So if GPUs are so awesome, why not just replace the CPU with a GPU? Well, a GPU will be faster than a CPU only if you have a large amount of calculations that can be done in parallel, which is rarely the case in regular computer usage. Also, GPUs are capable of performing only certain types of mathematical operations and don’t have the versatility of a CPU. But when you need to display millions of pixels all at once, the GPU’s parallel processing power really comes in handy. The calculations reach truly mind boggling numbers when you think of games like Crysis running at such high resolutions. In such games, the CPU generally handles stuff such as physics of the game, enemy/opponent’s artificial intelligence, etc while the GPU handles the graphical effects such as lighting, shading, shadows, textures, etc.

Available GPU options

Now that we know what a graphics accelerator card is and why we need one, lets see what the available options are. Deciding what graphics card you need depends on what you’re going to use your computer for. To make things simple, we’re going to go with three types of users - basic home/entertainment, casual gamer and serious gamer. As always, we’re not going to look at the fastest, fanciest stuff out there, but rather only at products that are good value-for-money. So our definition of “serious gamer” is someone who’s willing to plonk down Rs. 8,000 on a graphics card. While most might consider cards at this price as only mid range cards, they will still allow you to play all the latest games at fairly high resolution and most graphics details set close to max. We believe that anything above this price range is not worth the extra money since the gain is usually only minimal or just not necessary.

Basic home entertainment

AMD Radeon HD 4600

If your computer is going to be for just home use such as creating documents and surfing the web, or even as a living room entertainment center for streaming videos and playing DVDs/Blu-Ray disc, the basic GPU integrated in your motherboard should be enough. These are the cheapest and most common type of graphics accelerators. Since motherboards with GPUs onboard usually don’t cost any more than those without, you could say they’re quite literally free! Recommending one at this point is hard though since there’s more to choosing a motherboard than just the GPU. While the GPU in a motherboard might be good, other features may not be. We will be discussing the factors going into choosing a motherboard in a later edition of this Assembled series. But for now we’ll attempt to give you just an overview of the onboard GPU options. Intel is the largest manufacturer of integrated GPUs, but since we decided to go with an AMD processor in our article last week, we’re not going to consider them as an option in this article. That leaves us nVidia and ATi (AMD). While both have options to choose from, we cannot recommend any nVidia based integrated GPU motherboard due to a combination of factors such pricing, other motherboard features and performance. ATi on the other hand has the Radeon HD 3000 and HD 4000 series GPUs to choose from. These are excellent GPUs that support DirectX® 10 as well as ATI Avivo™ HD. The latter is a feature that greatly enhances video quality and also reduces the load on the CPU while playing HD videos and Blu-rays thereby making them excellent choices for HTPCs. These GPUs will also be able to handle most games at low settings. If you want to play an occasional game of Call of Duty and don’t care if the graphic details are low, these GPUs are a very good and cheap option. We’ll go into further details when we discuss motherboards in the weeks to come.

Pointers for Gamers

If you’re a gamer, you need something faster. Up till about the Rs. 8,000/- price point, the increase in performance is fairly proportional with the increase in price. Also, for the most part, both nVidia and ATi are priced equally. So the decision finally comes down to what your budget is and what kind of performance you want. Since nVidia and ATi are in such heated competition, they keep releasing new models and dropping their prices every few months. They also have several models at almost every performance level. So we’re just going to give you an idea about what to look for.

Let’s start with looking at the differences between nVidia and ATi cards. As far as regular gaming is concerned, there are no discernible differences. The differences are in additional features. nVidia cards support PhyX. This allow games to use the graphics card for physics calculations. Since GPUs are good at parallel processing, PhysX greatly enhances performance in scenes with a lot of moving objects, like hundreds of barrels being blown up, flying debris, flowing liquid or even just a flag blowing in the wind. ATi cards have a similar technilogy called Stream, but it is yet to be used in any games. Only a hand full of games currently use PhysX and even in them it’s just an enhancement and not a requirement to run the game. Another feature that nVidia cards have is 3D gaming. These cards can convert any games into an immersive 3D experice, but the 3D montor and shutter glasses that you need are well above the average consumer’s budget. A useful feature that ATi Radeon HD 5000 and 6000 series cards have is Eyefinity. This allows you to connect upto six monitors to just one video card and also play games on them. So if you have more than two monitors and/or plan on doing any multimonitor gaming, ATi is the way to go. Some of the newer cards wil boast DirectX 11 compatibilty. While it is a good feature to have, we’re going to overlook it since you will have to get a high-end card to be able to turn those features on and still get playable frame rates. For this article, we are assuming that you are just an average consumer who doesn’t plan on getting half a dozen 3D monitors and would rather use your life savings for slightly more important things like food, clothing and a better smartphone!

nVidia PhysX in action

ATi Eyefinity

nVidia 3D Vision

Serious Gamer

If you want to be able to play all the latest games at high resolutions (1680x1050 or 1920x1200) with all the detail levels set at maximum or close to it, you’ll need something in the Rs. 8,000/- range. The ATi Radeon HD 5770 is a good option. It supports DirectX 11 and Eyefinity. nVidia does not currently have any card at this exact performance/price point. The slightly more expensive GeForce GTX 460 768MB card is also a very good choice. It may drop to this price point any day. If you want something a little cheaper, the GeForce GTS 450 and the GeForce GTS 250 (a.k.a. 9800 GTX+) are good options.

Casual Gamer

If you’re a casual gamer, you could opt for something around the Rs. 2,500 – Rs. 4,500 range. By ‘casual gamer’, we’re talking about someone who enjoys gaming, but is okay with lower resolutions (1280x1024 or 1280x800) and setting all the graphic details to medium. Less graphically intense games such as MMOs like Warcraft and older games like Half Life 2 will run very well on these cards.Newer games like Call of Duty and Bioshock will also run albeit at lowers resolutions and detail levels. Keep in mind that in this price range, a small increments in price will give you a considerable increase in performance. So paying a few hundred rupees for that faster model might be worth it. If you’re on a tight budget, the integrated ATi Radeons we mentioned above might be enough for you.

The website, Tom’s Hardware, has a monthly “Best Graphics Cards For The Money” article which is a must read if you’re in the market for a graphics card. Their hierarchy chart should give you a rough idea about the sheer number of models and how they match up against each other. However, keep in mind that prices and availability could vary quite a bit from what is quoted there, since they would be looking at the US market, whereas you would be buying your graphics card in India.

Final thoughts

A few final things to keep in mind while buying a video card are connectors, size and power consumption. Nowadays many graphics cards support multiple output options such as VGA, HDMI and DVI, but if you already have a monitor/TV with a specific type of input, you want to make sure your video card supports it. The card’s physical size is another issue if you have a small case. Some cards can be upto a foot long and need plenty of space not only to sit in, but also for ventilation. We cannot stress these two points enough – the monitor/display connectivity and the available space inside the PC chassis that you have, or are going to buy. Please ensure that the graphics card that you plan to purchase would provide the necessary output connection for your display output, and that it would fit into the PC chassis that you have. Power consumption is another thing to look for. The more powerful the card, the bigger and more expensive your PSU (Power Supply Unit – or SMPS) needs to be. A GeForce GTX 580 drinking 500W is not going to help your electricity bill either. The cards we’ve suggested in the in the Rs. 8,000/- range consume about 200-250W under load. (So your Power Supply Unit – or SMPS – should be able to handle this load, in addition to the power requirements of the other components of your computer)

We hope this article gave you an idea about what to look for in a graphics card. Stay tuned for our next article in this series where we’ll unlock the mysteries of hard drives.

Other articles in the Assembled series:

Choosing the right CPU

Hard drives made easy

All about motherboard basics

Selecting RAM, chassis case and Power Supply Unit


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