Why is a graphics card required in the PC

How to check which graphics cards will fit your PC

Friedrich Stiemer

The enormous backward compatibility of PCI Express has the advantage that even the latest, most powerful graphics cards fit and function on a mainboard from the early 2000s. There is one thing to watch out for.

EnlargeHow to check which graphics cards will fit your PC

Upgrading an aging PC with new hardware sounds a bit unreasonable at first. But it is surprising that even an old desktop PC is quite capable of operating a state-of-the-art graphics card of the caliber of an Nvidia Geforce RTX 2080 Ti or AMD Radeon RX 5700XT. Both top models work in almost all systems that have been manufactured in the past ten years - probably even with even older configurations. However, there are also some restrictions.

To ensure that an up-to-date graphics card works with your PC, the following points must be met: You need a PCIe x16 slot (PCI Express) on your motherboard, sufficient space in the housing, a power supply unit with 8 and 6-pin PCIe -Graphic connectors (PEG for short) as well as a CPU-RAM team that is fast enough not to turn out to be a bottleneck.

EnlargeThe Nvidia Geforce RTX 2060 Founders Edition graphics card has the power connections on the back, but positioning on the top is more common.

The enormous downward compatibility of PCI Express has the advantage that even the latest, most powerful graphics cards fit and function on a mainboard from the early 2000s. From the original PCIe 1.0a / 1.1 standard to the current PCIe 4.0 generation and even in anticipation of future 5.0 and 6.0 standards, every card that fits into the elongated slot should theoretically work. PCIe x1 cards can be installed in x16 slots or x16 slots can be operated with only x4 link speed. There are exceptions, but they are only caused by an improper PCIe implementation or poorly programmed firmware. PCI Express thus proves to be quite stable, especially with regard to earlier standards, which rarely offer such backward compatibility and future security.

Upgrading your PC with a new graphics card is therefore very easy - provided that your PC actually has a PCIe x16 slot. If that's not the case, we recommend upgrading more than just your graphics card. In theory, it is possible to use an x1-to-x16 PCIe adapter solution, but this is not advisable. If your motherboard does not have a x16 PCIe slot, then you should plan to upgrade the motherboard and thus also the CPU, RAM and possibly the power supply unit.

But not functioning is not the same as functioning. Not every old PC with a PCIe x16 slot can automatically use the latest graphics card monsters. An example: You cannot install a 320 millimeter long graphics card in a housing that only offers space for 270 millimeter long models. Many compact PCs will be limited in their options. Many pre-assembled systems often fall into this category.

To find out what length the graphics card can be, take a look at the housing manual. In the case of finished PCs, however, you often do not have a manual. In addition, the information cannot be obtained from the Internet. We therefore recommend using a ruler or tape measure and measuring the space.

EnlargeEven outdated PCs can usually be upgraded with modern graphics cards. However, there are limits to when the campaign is no longer worthwhile.

Measure from the expansion slots on the back of the chassis to the component that is most likely to interfere with the graphics card. It doesn't matter whether it's the drive bays, fans, or the front of the case.

Also make sure that you measure at the level of the primary PCIe x16 slot if possible. The primary slot is the one closest to the CPU socket. Also pay attention to where the PEG connectors are on the new graphics card. Most cards have them on top. However, on some models, such as the Nvidia Geforce RTX 2060 Founders Edition, they are on the back. If the cables are too short, commissioning will be quite difficult.

However, we generally recommend that you allow for some buffer when measuring the length. Because even if you measure 300 millimeters of space and exactly this length is specified for the desired graphics card, it could be tight. Therefore, subtract a flat rate of 20 millimeters from your measurement and buy a graphics accelerator that is shorter. Then you are on the safe side.

The energy requirement is also an important criterion. If you have a PC built before 2015, chances are your power supply doesn't have 8-pin PEG plugs. However, these are a prerequisite for many faster cards today. 6-pin PEG plugs have been around for a long time, but they are still omitted in some inexpensive power supplies. If you have a PC from a large OEM like Medion or Dell, you may not even be able to swap out the power supply for a newer model with the required 6 or 8 pin connectors.

It is also important to note that there are adapters available - such as 4-pin Molex to 6-pin PEG plugs or 6-pin to 8-pin adapters. However, such solutions are not advisable. Because melted wires, short circuits and even fires can be triggered by them. It is best to buy a new power supply unit if you do not have the appropriate power connections available. In terms of capacity, you shouldn't go to the limits of your power supply. If, for example, a 500 watt model has two 8-pin connections, it could theoretically even supply an Nvidia Geforce RTX 2080 Ti.

EnlargeIf you do not have a PC manual to look up the graphics card dimensions, you can easily determine these with a classic tape measure.

But your CPU, motherboard, RAM, and other components also require energy. And even if your PC only uses 400 watts maximum, it is not advisable to run the PC that close to maximum. In fact, the optimum efficiency is often 40 to 60 percent of the nominal power of a power supply unit.

But even if you pair a current high-end GPU with a ten-year-old main processor, that doesn't automatically mean that all games will run at the highest frame rates. The bottleneck in these cases is not the older PCIe 2.0 standard. Instead, it is the outdated CPU that cannot handle the data volumes of the modern graphics card. If you have an even older PC or one that only supports the PCIe 1.x standard, it is probably better to upgrade the machine completely, not just the graphics card.

Ultimately, as with any PC hardware upgrade, you should consider your entire system. The good news is that if an old graphics processor fails, you can easily find a modern replacement that will still work, and probably be faster, and support new features. Just make sure that your PC has the necessary space and power connections. But: If your PC was built before the PCIe era and still has an AGP slot, then it's time to retire.

Tip:Buying advice: How to find the optimal gaming graphics card