How does frequency on a CPU impact performance? I.e. if I overclock a 2Ghz CPU to 4Ghz, is it +100% performance?
In: Technology
there are diminishing returns, as others have mentioned.
something to note is that clock speed is only a useful comparison for similar or the same chip. 2 chips can have the same performance with radically different clock speeds due to different architecture.
This is like adding Nitro to your car.
The engine (CPU) will work harder and provide more power but the rest of your car: the transmission, radiator, brakes, shocks, tyres, exhaust, alternator and differentials are all designed to operate with your default engine specs. So if you’re souping up your car by adding Nitro you need to additionally soup up your brakes, exhaust and tyres at least but you’ll be limited in terms of how much you can do – for instance you can only improve your cooling so much.
The same is true of overclocking a CPU in a computer.
Also your BIOS has a permitted range of settings which controls how much you can try to overclock. You could potentially create a custom bios but those limits in the BIOS are there for a reason. Actually overclocking a CPU by 100% would most likely melt the chip almost instantly.
Don’t be confused by features like Turbo Boost or Dynamic Acceleration which is designed into certain processors. This TEMPORARILY increases the processor power when needed. But this is not true overclocking as this is a default feature designed into these systems.
It theoretically is, yes. Double the speed is double the calculations made. However, every other piece of hardware outside of the CPU may not be able to handle it and will throttle the results back, depending what you’re doing. Basically the CPU will generate a new result so quickly that when it knocks on the door of another asset – they’re still busy. The easiest case to understand is a traditional HDD with a platter. It’s fairly easy to generate more data than an HDD drive can write. This is true for everything else, in increasingly complicated ways – a PC is the collection of a lot of moving parts and the CPU is just one component.
Right now CPU’s are in a state that they are less often the bottleneck to performance than they were in the past. So upgrading your CPU tends to yield less beneficial results unless you’re specifically running programs that bend the CPU over hard.
For general gaming the GPU is holding up the show more often than not. If you’re running commercial/design software then you still can benefit greatly from overclocking the CPU, but you need fast and sufficient RAM, and disk writing capability paired up with it.
In a nutshell your cpu does one thing every time the clock ticks. 2Ghz is 2,000,000,000 ticks per second. Increasing clock speed means doing more stuff per second.
Quick question, why don’t we use air conditioning/refrigeration technology for cooling PCs? The efficiency and cooling should be a no-brainer right?
Imagine if you could double the speed of your car. In an ideal world you could get to work/school in half the time. However, in the non-ideal, real world, there are things that prevent that such as speed laws and the other drivers that obey them. Even if other drivers don’t observe speed laws your tires are likely not up to doing twice the legal speed limit all the time, Your engine will get hotter and the oil will break down faster. The answer is it will make your computer faster but things like hard drive access, reads and writes to RAM, video rendering etc. will all stand in the way of the ideal.
pretend you can only work on cleaning your room when your friend Billy comes over. He doesn’t come over very often so you can’t work on cleaning your room very often, so it takes a long time to clean your room.
Now imagine that he can come over once a day. You can get your room cleaned even faster now.
Now imagine that he can come overo 10x a day. Your room is going to get cleaned up much faster now!
CPU frequency works the same. A computer can only do 1 tiny piece of work every time its clock ‘ticks’. The amount of work it can do in a ‘tick’ isn’t much, so the faster the clock ‘ticks’, the faster the computer can get work done.
The clock’s frequency is measured in this thing called ‘hertz’ (denoted ‘Hz’) that means ‘how may times per second’. so 10Hz means ’10 times per second’.
GHz means “billions of times per second”. So a 2GHz computer can literally do 2 billion things a second. a 4 GHz computer can do 4 billion things per second – literally twice as many things.
THat’s why a 4GHz computer is much faster than a 2GHz computer.
No it’s not a linear increase like that.
Personally though I find clock speed to be the best indicator of performance apart from maybe benchmarks. Like others have said, a faster clock speed means that the CPU can process more instructions in less time.
There are other factors though like cache size (the more data you can hold in cache the less fetches you need to make from main memory – and fetches are very costly in terms of performance).
Another factor could be the instruction set being used, essentially you get simple instructions such as ADD which takes the values in 2 different registers, adds them and stores the result in a third register. We’re getting a bit outside my area of expertise now but let’s say the ADD instruction can be completed in a single clock cycle.
Now lets imagine an instruction set which contains a multiply instruction which can complete in 2 clock cycles. And imagine we want to multiply 8×7.
How many ADD instructions does the first simple set need? Maybe 7.
How many MUL instructions does the more complex set need? Let’s say 1.
In these examples, we could say that a CPU with lower clock speed using the more complex instruction set might actually have better performance. To be clear, I’m not arguing that complex instruction sets are inherently superior, only in this made up example I’ve given.
In summary, it’s a balancing act, but for consumers I’d generally state that clock speed is a good indicator of performance.
It would allow the CPU to do CPU things twice as fast.
It doesn’t make your RAM twice as fast. It doesn’t make your disk twice as fast. It doesn’t make funny cat pictures download twice as fast.
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