Nabo’s Hardware School: The Processor/CPU

What to look for when buying A CPU/Processor

A CPU, centralized processing unit, or processor, is what does everything for a computer. All the calculations, and is the brain of everything. Needless to say this should be your best part, no matter what. There are very different design philosophies for pc builders. You have those who will spend money every six months because something was just released, whereas I prefer to build a PC that lasts several years. I am on a very tight budget, a college student, and I do a lot of other things with my PC. Having power is important, and both times I built my PC I did so by purchasing the best CPU available for the price.

So this starts us with different types of CPUs, and I am not talking AMD vs. Intel, but the number of cores, which is typically 2 or 4 (and now 6). What would be the advantage of having more cores? Well, certain games can utilize more cores, specifically strategy games or other games where a lot of physics is involved, Crysis perhaps. So, if you have a strategy game fix or if that is your genre, be sure to start with a quad core. Other applications can take advantage of this as well. Editing is a very specific way where having more cores can help. Be it video, audio, or photo, most modern editing programs have been written to take advantage of multiple threads.

This leads us to what makes a single core different from a quad core. This is because of how computers give a processor tasks. They do so in a list type format, each item on that list is referred to as a thread. So, a processor with more cores can do more tasks at once. This is only for things that are written to take advantage of multi-threaded environments, so not every program will see a benefit, but in today’s age most will.

With that out of the way, the next “thing” you need to look at is the speed of a processor. To do so, you need to understand something called a clock. Without getting too technical, the clock is what drives the CPU, the heartbeat. It “ticks” every allotted amount of time. So, it might take 3 ticks for something to look up and read a specific bit of the memory. It might take twice as long to write to that bit. So on and so on. What this means is the faster the speed, the smaller amount of time those ticks become. This does not mean that a 2.8 GHz processor is .2 GHz slower than its 3.0 counterpart at performing, but it means that the latter will be quicker. Some might not notice it, but others will when you get into situations where speed can be taken advantage of.

There is one other thing you should be aware of, and that is called cache. Cache is essentially a tiny hard drive for the processor to store things on. Why not just use the hard drive? Well, it is because cache, and ram/memory, has the advantage of being hundreds and thousands of times faster. Optical media and USB drives being the slowest, hard drives being quicker, then ram, then cache. What this allows the CPU to do is perform things on certain tasks that are done a lot very quickly. To complicate things there are different levels of cache. Each core has its own, then each pair of cores shares what is called the L2 or level 2 cache, and most processors have what is called L3 cache, level 3, for all the cores to share. This allows one core to pass data to another core so that if a core is waiting for that specific piece of data then it won’t have to wait for it to be written and then read by the other core. So, when buying a processor, trying to decide between several, you might want the one with more cache, and the one with L3 cache instead of just L1 and L2.

Now that you know the basics you might ask, what is the most important of these and what is a good processor? Well, I would not tell anyone building a computer today to go with anything other than a quad core or better. You can buy quad cores for a few dollars more than a good dual core. So what speed should you get? Well, most people doing any type of video watching, editing, or gaming would be smart to go with a fast processor. Since the spectrum of speed typically goes from 1.8 GHz up to right around 3.6/3.8 GHz, a fast processor to me would be 2.8 GHz or better. This will not only help you get things done faster, but extend the life of your computer for years. Most laptop owners wonder why things are so slow, the first thing I do is tell them to take a look at their processor speed, typically 2.2 GHz or less. These two things along with socket type and less so cache help to determine which you should choose, but these two are the most important. I will get into socket type when I discuss motherboards.

With that little bit of education you should be able to get yourself started. Find out what kind of a price you want to spend on your computer. Let’s say two scenarios, $500 or $1000 builds, I would spend 100-150 and 200-300 on each respectively. That is around one quarter of the budget. It might seem like a lot, but remember, and we will get into this more in-depth in motherboards, but replacing a CPU isn’t as simple as taking it out and putting in a new one, it usually involves new ram and a motherboard.

Just a note, I don’t have anyone to look over these before I post them, if you want the job PM me.

Chip Size and Speed

Some of you might be wondering what the chip size has to do with performance. What is the reason for having a 32 nm chip as opposed to a 45 nm chip? Well, the answer is twofold. First, the die that the chips are made from will yield more chips if they have a smaller area. The second is that when you have a smaller chip die, you have a smaller distance between components on those chips. This leads to much faster speeds because the electrons travel at a set speed and the only way to make the performance faster is to decrease the distance they have to travel. That is why in motherboard design things like the processor and memory are right next to each other, decreasing the travel distance and increasing the possible speed, therefore performance.

That leads to one question, what is the downside of a smaller chip? Well, the result of a smaller chip is that the pathways have much less of an ability to cool down, resulting in a hotter running chip. Sometimes this can be overcome through a cooling design, but in other cases it cannot. Another negative of a smaller chip is the risk of pathways crossing and electrons jumping from one path to another, essentially creating a short and damaging the chip. Shielding to prevent this takes space, which results in a larger die being required until the shielding can be perfected on the smaller die size.

Now, what does this mean when you select a processor, video card, or motherboard? Well, typically manufacturers release revisions of chips. One based off the previous, but having fixes and changes to improve performance. One of the most typical changes is a die shrink, resulting in faster performance on an already proven chip layout design. So be sure to look out for the newest revisions of chips, and find out what has changed between a newer revision and its older counterpart before you decide which to base your computer on.

07.12.2010 | Categories: computers, cpu, gaming, General, hardware, PC, processor, school, technology | Tags: 87, a, buying, chip, cpu, fan, for, gaming, hardware, look, nabokov, PC, processor, school, size, speed, to, what, when | Leave A Comment »