AMD vs Intel: Dual- or quad-core
There are three main processor families from Intel: Core i3, Core i5 and Core i7. As a general rule of thumb, these are in order of increasing power and price, so a Core i7 is more expensive, but more powerful than a Core i5, which in turn is more expensive and powerful than a Core i3. There is some overlap between the families, though, and you might be better off with a top of the range Core i5 than a bottom of the range Core i7, for example.
Processor capabilities and power within each of these types of families varies and after choosing whether to go for an i3, i5 or i7, you should consider the number of cores. Each core is basically a processor in itself and having more cores enables a computer to multitask more easily. Some programs can allocate different tasks to different cores and so perform several simultaneously. More cores mean faster, more responsive software.
All Core i3 processors have two cores. Core i5 and Core i7 processors can have two or four cores and four-core CPUs (quad-core) perform better under heavy workloads. Check the number of cores before you buy a PC
AMD vs Intel: Hyper-Threading
An Intel technology called Hyper-Threading enables one core to appear to be two, two cores to look like four, and four to be eight. Virtual cores are not as good as real cores, but they enable a processor to make more efficient use of its power. Although Core i7 processors only have four cores like many Core i5s, most are able to run eight threads (eight virtual cores) compared to the Core i5s four. This is one way in which Core i7 processors are better than Core i5s. Check the number of threads a CPU can run when buying a PC.
AMD vs Intel: Cache
Processors contain on-board memory called a cache and this is used to store frequently accessed data. It can be accessed much more quickly than the main RAM in the computer and the larger the cache, the more information a processor can store in it. This means it needs to access slower main memory less often and a CPU with a bigger cache functions more efficiently than one with a smaller cache.
Core i3 processors have 3MB or 4MB of cache and the ones with 4MB should be a tiny bit faster. Core i5 processors have 3MB, 4MB or 6MB caches. If all other factors are equal, Core i5 CPUs with 6MB perform better than those with 3MB or 4MB. Core i7 processors can have 4, 6 or 8MB caches and the increased cache size is another way in which the Core i7 is better than the Core i5. There are some Core i7’s with two cores and 3MB of cache, but some Core i5s with four cores and 6MB of cache. This is one reason why some Core i5’s can be better than some Core i7s. Don’t assume a Core i7 is best.
AMD vs Intel: Clock speed and Turbo
At one time, processors had a fixed clock speed and they ran at that speed the whole time. These days, CPUs are more like the engine in a car and they idle at rest, run at moderate revs during normal use, and when you need the power you can floor the accelerator and rev to the red line. Processors are similar and they idle at less than 1GH, but give them work to do and they run at 2GHz, and when needed they can accelerate to over 3GHz.
A CPU’s clock speed is an indication of the speed when running normally, but some models have a turbo mode which allows them to exceed this for short periods where extra processing power is needed. Processors with high clock speeds are best, but those with turbo mode are better. When comparing processor speeds, check whether it is the clock speed it can run at all day or whether the figure is the turbo speed it can reach only briefly.
This Core i7 is idling at 0.79GHz, runs at 2.4GHz, but can turbo up to 3.4GHz
AMD vs Intel processors: integrated graphics
Nearly all of Intel’s processors come with integrated graphics now. Models include Intel HD Graphics 4200, 4400, 4600, and 5000, and Intel Iris Graphics 5100 and 5200. Higher numbers mean better performance, so if two CPUs are the same in all other respects, the one with the higher graphics number will offer better performance. However, if the PC or laptop has a separate graphics card then integrated graphics is pretty much irrelevant. Budget PCs tend to use on-board Intel graphics while gaming PCs have a dedicated high-performance graphics card, so it’s only an issue for budget PCs.
Intel vs AMD: which is best?
Most of this article has been about Intel processors and this is partly because they have the largest market share and partly because Intel currently has the best processors. AMD was a serious challenger at one time, but these days the company only competes at the budget end of the market. Everything we've said already applies equally to AMD CPUs though, so more cores means better multi-tasking, bigger caches mean better performance, and some have a base speed (normal running) and boost speed (turbo).
AMD processors to look out for include the AMD A10-7700K, AMD A8-6600K and AMD Athlon X4 750k in budget PCs, and the AMD FX-4300 in slightly better ones.
As for answering the big question, which is best - Intel or AMD - it is often difficult to decide for yourself because it's rare to find two similarly priced laptops or PCs with identical features - motherboard, graphics card, RAM, hard drive, etc - yet one with an Intel chip and the other with AMD. Should you happen upon such a situation, it's usually best to choose the one with an Intel processor.
The thing is, AMD processors tend to be cheaper so if outright performance isn't your top priority, you might find that a computer with an AMD processor has additional features (more RAM or a larger SSD, for example) over an Intel-based one at the same price. In that case, it's all down to what you want from a PC or laptop. With a laptop, you're more likely to be concerned about weight, battery life and screen quality than processor power. Here's more laptop buying advice. For PC buying advice, see What's the best family PC? or How to choose a gaming PC.
