How to choose the right graphics card?
Of all the electronic components that make up a computer, the graphics card is an essential device for the visual experience. It is an integrated circuit that deals with the processing of data and its transformation into visible information, which is revealed to the user through a monitor, television, projector, etc. In this article, we will explain the different types of graphics cards, their components and their main characteristics and show you how to choose the right one for you.
Types of graphics cards
There are two types of graphics cards that are determined by RAM usage: integrated and dedicated graphics cards.
Integrated graphics cards
In the case of integrated graphics cards, the GPU (graphics processing unit) does not use the RAM of the card itself, but uses the VRAM (video memory) of your computer. They are also built into the same chip as the CPU (your computer’s processor). This option is the least expensive and may be suitable for non-graphic intensive activities.
Dedicated graphics cards
Dedicated cards have their own independent memory source. Therefore, they are kept outside of your computer’s RAM, ensuring better performance. It must be taken into account that they consume more energy, so it is recommended to have a good cooling system. They guarantee a better visual experience in the most demanding games or graphic design programs. They can be found in two formats: with a direct connection to a port on the motherboard or in MX format for laptops.
Graphics Cards for Desktops and Laptops
More often than not, today’s desktop computers have dedicated graphics cards. In the case of laptops, low-end computers almost always use integrated cards, unlike high-end computers which have their own dedicated graphics cards.
Components of a graphics card
Here are the elements that make up a graphics card and its features:
GPU (graphics processing unit)
This term refers to the graphics core, i.e. the brain of our map and where all the necessary operations are carried out. The GPU accelerates the performance of various applications related to image processing.
Here are the specifications of this component which will determine to a greater extent the quality of our graphics card. These are:
It is measured in MHz or GHz (GB being a higher unit of measurement than MB) and indicates the speed at which the cores of a graphics card operate. This is one of the most important variables in determining card performance. The higher the clock frequency, the faster the data processing. Low-end cards run around 825 MHz. and high-end cards can exceed 1200 MHz. Two types of clocks are usually specified: Base Clock (the processor’s base clock) and Boost Clock (the clock that hits the temperature and power consumption limits).
- Number of shader processors
They are called CUDA cores (on NVIDIA cards) and stream processors (on AMD cards) and are primarily responsible for pixelating textures and object geometry. These are the most important elements of the power of our graphics card because the more shaders there are, the more power there will be. A low-end model will have around 192 cores, rising to 3594 cores in the more powerful models.
Number of pipelines In charge of changing vertices and lines to pixels when going from 3D to 2D images.
It is a sub-processor which takes care of the transcription in memory of the pixels and therefore of the texture. For example, it directly affects the FPS (Frames Per Second) in a video game.
- GRAM (graphics random access memory)
Graphics cards require memory to function properly.
The so-called random access graphics memory consists of a special built-in RAM memory that allows data concerning graphics to be stored on demand and thus avoids saturating the main RAM memory of our computer. As we mentioned before, dedicated cards have their own RAM memory.
Less decisive in the performance of our card than that of the GPU, the quality of the GRAM is subject to various factors:
It is measured in GB or MB. The higher the capacity, the less time it takes to process the data. It can be 4 GB, 6 GB… and even 16 GB, if we refer to the high-end models.
- The interface or the data bus It is measured in bits and refers to the amount of data that can be sent or received per unit time. For example, if we have a 128 bit bus, it is able to send and receive up to 128 bits per clock cycle.
The more bits, the more data can be transferred. There are different types, such as PCI Express (Peripheral Component Interconnect Express). These are slots that allow communication between the device and the computer’s motherboard. Their size is indicated by an x, usually preceded by a number (eg x16), which reflects the size of the slot. To clarify, the higher the value of the number, the larger the size.
- Speed It is measured in MHz or GHz (effective frequency). It is complementary to the data bus, since it determines the data transfer speed.
- Bandwidth It is generally measured in GB/s and is the result of the combination of the two previous variables: it is the product of the memory interface (bits) by the effective frequency of the speed divided by 8:
AB [GB/s] = (Memory interface [bits] ∙ Effective frequency [GHz]) / 8
For example, if we have a 128-bit memory interface and a speed of 3200 MHz (equivalent to 3.2 GHz), we have a bandwidth of 51.2 GB/s.
Following this example, the PCI graphics have a 32-bit data bus, a frequency of 33MH, and a bandwidth of 132 Mb/s.
Regarding the development of different types of GRAM used in cards, the GDDR3 version launched by Samsung in 2003 was followed by GDDR4(2005), GDDR5(2008), GDDR5X(2016) and GDDR6(2018). At least they are the most popular, they have been rated highest in their release date and in this article they have been ranked from low to high. In this regard, it is also worth mentioning the HBM memory used in very high-end models.
In the end, the main thing is the bandwidth which depends on two parameters (speed and interface). For example, a 128-bit graphic and GDDR5 will be better than a 256-bit graphic and GDDR2.
RAMDAC (Random Access Memory Digital-Analog Converter)
As its name suggests, the function of the Digital-Analog Random Access Memory Converter is to convert a digital signal that allows the output device to interpret the data.
On the other hand, it directly affects the refresh of the screen. It is usually measured in MHz and the higher it is, the more it can support different monitor refresh rates.
Today, the vast majority of monitors support digital images. For this reason, they are increasingly in disuse.
The best known outputs to make the connection between the graphics card and the monitor are the VGA output (to transport an analog image), DVI (for digital displays and the replacement of the previous one) and HDMI or DisplayPort (technology for transmission of digital images that also have the ability to transmit high definition video and audio at high speeds).
It follows from the descriptions above that we recommend that you purchase the latter option.
This section refers to the connection systems between the graphics card and the motherboard of your computer. In the same way as it happens in the GRAM, they determine the relation between the bus architecture, the frequency and the necessary bandwidth in a defined time.
These devices include heatsinks and fans, which are extremely important for avoid overheating which could damage the graphics card.
The radiator is a passive silent device (no moving parts) which helps extract heat. The larger the surface, the greater the cooling capacity.
Fans are active devices, therefore noisier, which move the air closer to the map. They are less efficient than heatsinks, so we recommend having both.
There are also alternatives that use water as the cooling element (watercooling) instead of air.
Last but not least, we are going to talk about the power supply of graphics cards, devices that consume a lot of energy. Therefore, it is important that they do not exceed the power provided by the PCIe port (bus that allows adding expansion cards to the computer) of the motherboard, which has 75W.
If higher consumption is required, it is also possible to avoid connecting the card directly to this port and to do so to a power source by means of a specific connector.
Once all the components have been analyzed, it is important to take into account the balance between them for proper operation. For example, it is not enough to have a high capacity card if you have a reduced bandwidth.
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