Graphics card buying guide

[siopao1984]

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Graphics card buying guide

To start off with, we would like to say that for the purposes of this article a graphics card is only really useful to someone looking to play games ( we are not considering ‘professional’ graphics cards like AMD FirePro and Nvidia Quadro cards). Although, there are a number of other purposes a graphics card may come in handy for such as Folding at Home (mainly Nvidia cards) or running multiple monitors.
However, in this article we will be focusing on graphics cards for gaming and how you would go about picking one. When you pick a graphics card these days the choice isn’t a simple as it may first appear, there are a multitude of factors that need to be taking into consideration to make sure you get the most out of your graphics card. We will be taking each of those factors and dissecting the main issues behind them further. The factors we think are important when choosing a graphics card are:

• The power supply requirements
• The number of screens you will use and at what resolution
• The performance of the rest of your system, the CPU in particular
• The amount of space in your case

We do not necessarily think your budget is an issue that is important when choosing a card, at the end of the day you make the ‘selection process’ of your graphics card using your budget and the performance figures of the potential candidate cards. Once you have narrowed down your choice to a handful of cards then it is important to consider the above criteria to then figure out which one is the most appropriate for you, note the card with the ‘fastest’ performance is not always the best card to get in most cases.
When it comes down to the question of ‘AMD or Nvidia?’, we don’t think this is a criterion that bares consideration. A graphics card is a graphics card and both AMD and Nvidia have their own unique perks but no one brand of card brings significant advantages over the other when it comes to gaming.

[siopao1984]

POWER SUPPLY REQUIREMENTS

When we refer to power supply requirements for a graphics card it is not simply a case of Wattage. There is a lot more to it than that, although Wattage is still important. Other things to consider are:

• Whether your power supply has the required connectors
• If your power supply rails contain enough amps
• (Total Wattage as mentioned earlier)
• Efficiency of your power supply

Your first core consideration when choosing a graphics card is: ‘can your system power it?’ If you already have a power supply then you have to work out how much in total your entire system consumes, you can do that here. Once you’ve worked that out, you should consider your power supply’s efficiency. For example an 80 PLUS power supply will mean you could lose only 5% of its maximum stated Wattage to heat waste whilst a really cheap 500W power supply may lose up to 30% of its maximum state Wattage because of its poor efficiency. (i.e the power supply may pull 500W at the wall but only deliver 400W to your system) Although if your power supply’s wattage is ‘continuous’ it should deliver its stated wattage irrelevant of its efficiency. With that in mind:

Power Supply Capacity – system power consumption = spare power capacity

Once you’ve worked that out its then a good idea to look at the graphics cards you want, find a review with power consumption figures and then determine if you’ve got enough power to meet the maximum potential draw of the graphics card. Give yourself about an extra 5-30% on what it says the graphics card consumes to make sure you account for the efficiency of your power supply.

The range of connectors is also important, for most graphics cards above the entry level of performance you may require any combination of 6 pin or 8 pin. Just in case you’re not sure and want to double check the 6 pin is shown below, and the 8 pin is shown below that.





With regards to Amps it’s really difficult to give an accurate estimate of what kind of numbers you need. As a general rule if your power supply is made to an 80 PLUS standard by a well respected manufacturer such as OCZ, Seasonic, Corsair or Thermaltake then you will have enough power on the rail(s) to power your cards providing the wattage is high enough and the power supply has the appropriate connectors. Remember the 6 pin provides a maximum of 75W, the 8 pin provides a maximum of 150W and the PCIe bus provides another 75W. This is just a general word of warning, as a lot of ‘lower quality’ power supplies will claim power delivery of say 600W but then the PCIe power connectors won’t be able to deliver enough power as they lack the required amps. You can also convert other power supply connectors such as the 4 pin molex into a 6 pin or convert two 6 pins in to one 8 pin. Sometimes this can be an issue (mainly for the molex to 6 pin coverters) as those molex connectors will tend to have less amps than a 6 pin connector should have as the molex connectors are intended to power hard drives not power hungry graphics cards.

Our advice is simple, you can either:

• estimate the power consumption of your system and work out how much you have available to you in terms of watts.
• go by the manufacturers recommendation for minimum power supply requirements.

Both those methods should give you a safe ballpark figure for how much power you can spare for a graphics card. Although it is worth noting that you can just upgrade your power supply when you upgrade your graphics card if this is easier for you. Power supplies are easier to change and more affordable to change than other components that can potentially be limiting like the processor which we will touch on in a bit.

[siopao1984]

HOW MANY SCREENS AND AT WHAT RESOLUTION?



AMD and Nvidia have been flaunting Eyefinity and Surround technology now for a while but the reality of it is that most of us gamers still only use a single screen. Only a very select few actually have the multiple screen set ups required to utilise Eyefinity and Surround technology. That said you may indeed be one of those people.

The reason why we mention screen size and screen resolution is for quite an important one. The issue with screen resolution is reflective of how much frame buffer or VRAM you will actually need and this is important as if you have too little VRAM you will end up with a scenario when you suffer performance drop because you may lack the VRAM to render certain levels of texture or if you have too much then you will find yourself in a scenario where you have probably paid more for a graphics card than you need. There is no definitive mathematical rule but we have found that the following rule seems to stand up quite well: 1GB for 1920 by 1080, 1680 by 1050 resolutions or higher and 512MB for 1440 by 900 monitors or less.



Of course in a logical fashion if you have three 1080p screens it makes sense to say that you will need 3GB of VRAM, or if you have three 1366 by 768 monitors then you would need about 1.5GB of VRAM. Although what you must consider is we are writing primarily about gaming purposes. Should you wish to utilise 3 monitors for everyday applications like presentations and office documents then of course you would only need a card that had the ability to support 3 screens with a much smaller amount of VRAM.

Another issue crops up when talking about multiple monitor set ups and that is of Eyefinity and Surround support. Some cards do not have built in Eyefinity or surround supports whilst some do. For example the HD 5870 supports 3 displays out-of-the-box. Whereas Nvidia’s GTX 560Ti does not support more than 1 monitor out-0f-the-box. You must purchase another card to run in SLI to get surround support. But as we already mentioned earlier most people will still use only 1 monitor so in that case the aforementioned rules apply well.

[siopao1984]

CPU PERFORMANCE



When it comes to gaming performance the two main determinants of system performance are the processor and the graphics card. Obviously if you are picking a graphics card your processor must be capable of allowing your graphics card to perform to its maximum capacity. Your CPU can limit your graphics card in games but your graphics card cannot limit your CPU. The term commonly used to talk about the CPU limiting Graphics card performance is ‘bottlenecking’. Essentially what you must consider when getting a graphics card is whether your CPU ‘matches it’ in terms of performance.

The easiest way to illustrate this is with a few examples of how to do it and how not to do it. Lets for example take the GTX 550Ti, this is a entry level graphics card. This card would work fine with anything from an AMD triple core or higher or with an Intel Sandy Bridge dual core or higher. If you were to bottleneck this you would have to have something ‘worse’ than those processors, for example say you have an old AM2 system and you decide to put a GTX 550Ti with an AMD Athlon 64 X2 4000+, this would be an example of a bottleneck.

So you’ve got a bit more money to spend and you pick a high end graphics card, you could go with the HD 6970. A very powerful card in its own right, more than capable of delivery multiple monitor high resolution performance, but what kind of CPU would you need with this? Well this Graphics card cost around £250+ and we would say if you’re an AMD user you would need at least a Phenom II X4 or an Intel Quad core (from LGA 1366 onwards) to unlock its full potential. How would bottleneck this kind of card, well something like an i3 2100 would probably be too slow to allow this HD 6970 to perform to its full potential.

There is no maths to this, no formula which can always give you the right answer. Its about using your common sense and good judgment. In an effort to provide something objective for you to work with we would say your CPU should cost at least 65-70% of the value of your graphics card in order for it to not be a bottleneck. E.g a 2500K with a GTX 570 or a Phenom II X4 955 with a GTX 560 Ti. The same formula seems to stand up quite well for multi graphics card configurations as well. For example if you have two HD 7950s which is about £700 worth of graphics cards then you would need an i7 3930K (about £440 worth of CPU) in order to not bottleneck it.

A good way to test if a CPU is bottlenecking a graphics card is 3D Mark Vantage. If by overclocking your CPU (or by using the card with a better CPU) you get an substantially increased 3D Mark Vantage GPU score (by more than about 5%) then your CPU is bottlenecking your graphics card.

[siopao1984]

SPACE CONSTRAINTS

The final issue when picking a graphics card that we want to mention is space requirements. This applies in both a vertical and horizontal sense. By horizontal we mean the length of the graphics card, this is the most common issue of space you may encounter. By vertical we mean the height of the graphics card, how high is the graphics card in relation to how much space your case has available to it, this tends to only be an issue with small form factor cases and systems.

For example if we look at this Antec One case below, you can see that there is a maximum graphics card length of 10.5″ which means monster cards like the HD 6950/6970 and GTX 580 are essentially ruled out as they both reach 10.5″ or more in length. What this also fails to mention or show is that once you have installed a hard drive in the bay which lines up with where your graphics card would go you further reduce the space available as the back of the hard drive sticks out reducing the room by a further inch or so.



Another thing to consider is if your graphics card doesn’t fit, can you make it fit by removing the hard drive cage. In the Antec one above that is clearly not possible as it is rivetted in but in other cases it is possible such as in the HAF 912 case where with the hard drive cage in you have roughly 11″ in space when removing the hard drive cage you get about 4.5″ more in space allowing for the largest card on the market the HD 6990.



With regards to vertical height we are talking now about whether your particular case supports full sized PCI-E cards or whether it only supports half height PCI-E cards. This is a simple thing to see, simply check the PCI brackets on the rear of the case and if they are half of what they should be then your case supports half height graphics cards. Although sometimes your case will support full sized PCI brackets but not full sized cards internally. Therefore it is always important to measure available space. Immediately below you can see a half sized card with a full sized PCI bracket, below that you can see a half sized PCI bracket comparison:

[siopao1984]

We have taken you through a brief look at some non-performance and non-cost factors to consider when buying a graphics card. At the end of the day its really quite simple to see which card performs the best and which cards cost what but its harder to consider the other factors we have looked at that were:

• The power supply requirements
• The number of screens you will use and at what resolution
• The performance of the rest of your system, the CPU in particular
• The amount of space in your case

As we mentioned when considering power supply requirements it is important to look at the total Wattage, the number of Amps, the required connectors and overall level efficiency of the power supply you intend to be using. When considering the number of screens you will be using and at what resolution this helps decide the amount of VRAM or graphics memory you will need and whether the card you picks has support for AMD Eyefinity and Nvidia Surround technology.

We looked at how the performance of the rest of your system is vital. The CPU is the main limiting factor graphics cards face and consequently we think that your CPU should cost at least 65-70% of the value of your graphics card you will be buying (based on new average RRP prices for the models) to avoid bottlenecking. The final issue is one of paramount importance, Space. You need to make sure your case has enough vertical and horizontal space to support both the length and height of your chosen graphics card.

We hope you found this guide useful and if you have anything to add please post them in the comments box below.

[philcarr]

nice post... very informative

[chang87]

nice one boss siops... newbies should really find this helpful... +1

[CrasHBURN]

Graphics card buying guide:

Step 1:

How deep is your pocket?

Step 2:

Buy

LOL!

[3kster]

hahaha idola jud sa mga comment ni CrasHBURN oi,. hahhhahah