The processor or CPU (Central Processing Unit) is the "brains" of your computer. It's a chip maybe around 1 1/2 to 2 inches square that contains many millions of transistors. As it runs it uses a lot of electricity and generates so much heat that a metal heat sink and a fan are attached to it that have to run constantly to cool it down to keep it from destroying itself. Physically you CAN upgrade a processor but it's not a trivial thing and best left to professionals or serious amateurs.

BUT...there is a way to "upgrade" your processor so-to-speak via software, called "Overclocking." If your old computer is pretty slow, you might consider it. What is overclocking?

"Overclocking is the action of increasing a component’s clock rate, running it at a higher speed than it was designed to run. This is usually applies to the CPU or GPU, but other components can also be overclocked."

The Howto geek

What you're doing when overclocking is manually telling your computer to run faster than its standard rate. You have to have a motherboard that allows for overclocking (many of them do). Can it damage your computer? Maybe, but probably not. If the motherboard allows for it then it was made to be overclocked. Start by reading this article "The beginners Guide to Understanding How Geeks Speed Up Their PC's." When through with that, then read this article in its entirety: CPU overclocking guide and tutorial for beginners. Overclocking can be a rewarding way to speed up your computer with little or no investment while gaining a great deal of knowledge about how your computer works.

FYI in most cases overclocking is not necessary. Adding memory and a solid state drive will make your old computer run fine. Overclocking is for extra credit and those that like tinkering!

INTERNET: This part refers to how your computer connects to the rest of the world. It's going to be either hardwired or wireless. Look over your old computer and determine how it connects. Do you have to plug a cable into the back that looks like the one to the left to connect to the internet?

If so, then it's hardwired; that cable is called an Ethernet cable. The other end of the cable has to connect to your home network, either to a switch or a router (we'll cover all that in a future installment regarding home networks). For our purposes, your computer's Ethernet port will be one of two kinds...Fast Ethernet (100BaseT) or gigabit Ethernet (GIGe). Fast Ethernet can hit speeds up to 100 mbps(megabits per second). GIGe can hit speeds up to 1000 mbps (1000 megabits per second or 1 gigabit per second). Obviously between the two you want GIGe. but while GIGe is currently found on all computer sold today, an older computer most likely has a fast Ethernet port. Is this a deal-breaker? Nope. Here's why: My current Comcast internet plan gives me 120 mbps. If my computer were using a fast Ethernet connection then it would knock 20 mbps off my internet speed, which is not tragic for day-to-day use. (If you were paying for speeds higher than 100 mbps but only had a fast-Ethernet capable computer, you'd be wasting your money). You could look for a USB to Ethernet converter; you plug one of these into a  USB port on your PC then the other side plugs into your Ethernet source. You could get performance up to 500 mbps out of this combination, but ONLY if you plug the converter into a USB 3.0 port, which might not exist on an older computer. You could also purchase a GIGe Ethernet add-in card for your PC, but the expense and complexity of it generally aren't worth your time. So don't lose any sleep if your older computer only has fast Ethernet (in the unlikely case you are paying for internet service significantly faster than 100 mbps, you should buy and install a GIGe add-on card. Here's a link to a GIGe card on Amazon for $9.90 that ships overnight and works with all Windows operating systems. Be sure your old computer has an available PCIE slot on the motherboard for it. It's got a 4 1/2 out of 5 star rating with 155 reviews).

If your computer connects wirelessly, then your computer has  WIFI built in; you might see a small antenna sticking out the back of the PC. Now WIFI technology has changed rapidly over the years, so you want to figure out what you have installed and maybe upgrade it if you're using older wireless technology to connect. Unfortunately, the world of wireless technology is filled with jargon and obscure acronyms, and involves more than just your computer. Let's de-mystify things.

When WIFI was first created, the Institute of Electrical and Electronics Engineers (IEEE to you), a global body that creates and maintains global electrical standards, designated the first wireless computer standard 802.11a (and 802.11b) - don't ask why regarding this particular nomenclature. This was in 1999, and these devices communicated at a speed of from 1 to 54 mbps. In 2003 802.11g equipment was released; it communicated at 54 mbps. You can see the progression in the chart to the right (from Wikipedia). Now the WIFI alliance, a non-profit group created by WIFI manufacturers, finally figured out that this naming convention was confusing to the average consumer, and so began labeling them WI-FI 1, WI-FI-2  etc., the higher the number the newer the rating and the faster the speed.  Again you can see this in the chart. What you need to know is:

1. Faster/newer is generally better

2. Your computer only communicate as fast as your router (access point) allows it to.

Let's me explain this.

Generally, all the standards are backward-compatible; that is, if your router/access point supports WIFI-5, but your computer's WIFI adapter is only WI-FI 3, it'll still work. It will just work at WI-FI 3 speeds because that's all your computer's adapter can do. BUT, if your router/access point is capable of WI-FI 4 and your computer's WIFI can do WI-FI 6, then you will be limited to the router speed of WI-FI 4 because that's all the router can do. You'll always be limited by the slowest speed of the Router/Access point and the computer WIFI adapterr.

Speeding up your wireless connection therefore involves not just your computer but your computer and your router/access point (I keep using the phrase router/access point because they are usually bundled together. An access point just broadcasts wirelessly; a router is a piece of equipment that connects multiple networks; consumer routers usually contains a firewall and an access point).

You need to do this:

First Google your computer model to look for the specs or look at the paperwork that came with it to see what WIFI standard your computer has built-in.

Check your ISP to see what service (speed) you're paying for. It could be anything from 25 mbps to 1 gigabit per second or higher.

Look up your router/access point to see what wireless standard is built into it.

Based on this information you can easily see where - if anywhere - is the best place to spend a few bucks to get faster speed if you need it.

EXAMPLE: You pay for a service plan from your ISP to get 75 mbps to your home. The old computer you're thinking of upgrading has an 802.11n (WI-FI 4) adapter, and your router/access point is an old one, 802.11g (WI-FI 3) capable. Where's the best place to spend your money? Well it's not in your computer but you'd be doing well to replace that old router. It's throttling your internet connection to (maximum) 54 mbps when you're paying for 75. Upgrading would benefit everything in your home that uses the internet. The existing WIFI adapter on your old computer should be able to handle your maximum internet speed so no change is necessary there.

What I'm saying here is that if you have an old router you might benefit greatly by upgrading it (not just your older computer but every computing device in your home). But if your old computer has older slow WIFI built-in, you would be wise to upgrade it to new WIFI capability. FYI USB wireless adapters are plentiful and inexpensive.

Here's one on Amazon for $13.99 that does WIFI 5...remember that it's better to plug into a USB3 USB port if your computer has one (and if the WIFI adapter is USB3-capable) but not tragic if you don't have one...you'll be limited to fast Ethernet-like speed, which should be adequate for day-to-day work.

What about the rest of the stuff you need for a computer - screen, keyboard, mouse etc.? We'll cover those in Part IV of this series.