Has hardware stopped improving like it used to in the last few years

Way back when we used Moore's law where everything improved every 16 months or so. 2X the speed then 4 X then 8x....... 128G then 256G then 512G etc. etc.
I must admit I don't keep up-to-date with things like I used to but it seems to me for ex, that we still have the same CPU chips as 4-5 years ago, i3, i5, i7 etc. even though I know that the i5 of today is not like the original i5.
Nevertheless this is why the question popped up in my mind.
Is a PC today actually that much better than that of 4 years ago?
and to stick to the comparison,
if we were to say that 4 years ago a PC was X amount of times better than one 8 years ago could we say the same for one bought today compared to 4 years ago.
My concern here is mainly Mother board, CPU, Video card and RAM

Yup Moore's Law still applies.

But... since now CPUs are multi-core, the software has to be programmed to use all the cores to see any benefits, which isn't always the case even today.

And most software have added features/bloatware that suck up any improvements in hardware performance, so you probably won't really experience any major increase in speed from a 4 years old PC in regular applications like Office and such. In some areas like games or video processing though, it is noticeable.

If, like me, you use software that needs a lots of muscle eg 3D renders, then hardware has really changed in the last 4 years. When I started using this forum around 2010 I was using an i7-930. It was a very hot cpu esp when o/c so needed a huge cooler + case fans (TDP 130W @ stock). Today I have 4770k's that are 2X as powerful and run a lot cooler (TDP 84W @ stock). The latest 6 and 8 core Haswell's are even more powerful. GFX cards also have more bang/buck today - 125GBP buys a card that will drive 4 HD displays.

Entry level hardware has also improved vastly. I recently built a i3-4130 system where the mobo could drive 3 HD screens using on-die GFX with ease.

> my $0.02

Thanks guys. One thing that was apparent to me is SSD and hybrid hard drives, which are more common now than before. But based on what I've been reading while I was waiting for a reply and what you have said I guess I could wait a couple of more years before buying a new PC. (My sound card, vga card and SSD are all 1-3 months old the rest is 4 years old.
There was one thing though which caught my attention, 4 years ago I was told that Windows 7 (or was it my MB) only allowed maximum of 12G RAM now I read some guy claiming to have 16G RAM. What is maximum allowed RAM based on?

Maximum RAM is first limited by the type of processor (32 bit/64 bit), then your motherboard (most recent ones support at least 32 GB max) and finally the OS.

32 bit Windows is limited to 4GB. Note that some alternative OSes (Linux for example) can work with more even on 32 bit.

64 bit Windows, it depends on the edition. For Windows 7 : it goes from 8 GB (Home edition) to 192GB (Ultimate). For Windows 8, it goes from 128GB (Core) to 512GB (Enterprise edition)

Oh OK. Having bought my PC while I was in Taiwan perhaps my Chinese not being too good I misunderstood the guy. I have Windows 7 Home Premium 64 bit. I guess I'll look it up to see what my limits are--OK found out 16G. Hmm! will I see much of a difference on Photoshop or games going from 12 to 16?

From 12GB to 16GB ? I doubt it won't make much difference.

Still depending on what you're doing in Photoshop for example, having more RAM limits Windows's access to the slower pagefile on disk.

To really know if having more RAM will benefit you : Open the task manager and check the Physical Memory Usage there.
Here are some good links that explain this :
See details about your computer's performance using Task Manager - Windows Help
Preventing low memory problems - Windows Help
Measuring memory usage in Windows 7 | BrandonLive

In re-reading all more carefully this time I have noticed that perhaps my MB does limit me to the max RAM i can put. Thanks oneeyed re: this and also thanks for the info provided by the link. Because of it I noticed how more often than not I can see that in the Task Manager for the Commit everyday stuff i end up using 3/12, 4/12 once in Photoshop (with browser and Skype in the background) it goes to 5/12. However the 12 turns to 13 and the 5 to 12 when I start using the OnePhoto Perfect Effects plugin. This suggests that perhaps 16G RAM if possible for me would be a good idea. Too bad they don't sell 6GB sticks. My current setting is 2GB/4GB/2GB/4GB which implies to get 16 I would have to get rid of 2 cards while if 6GB existed I would need to replace only one. I was also surprised not to see a lower price in RAM than 4 years ago.