In spite of always buying new computers and garbaging the planet, this is a nice site to know if you want to upgrade your CPU : https://www.cpu-upgrade.com/
That way you get which better CPU is compatible, which performance upgrade you can get, the TDP (be careful about watts especially on portable computers) as well as the maximum RAM bus speed.
Watts = heat = throttling (or breaking) if not supported or in case of bad dissipation. Cleaning your fan is often a good way to make your computer (especially portable) work much quicker. You also have plenty of Youtube videos showing how to replace the thermical paste on old computers as nothing is eternal. Moreover, you can add an external fan to ease cooling in case of intensive processor use. It is funny to see how portable computers easily throttle making users buy costly Ferraris working at … horse and buggy pace.
You can also easily understand that CPU doesn’t make it all and performance on CPUs from the same generation can be relevant upgrading for example from i3 to i7 but not so much if you already have an i5 … so usually upgrading an old PC comes with replacing the HDD by an SSD and adding some more RAM. And these 2 points are the most impressive ones.
A few tricks to simplify explanations when you upgrade RAM for example from 8 to 16 or 32 GB (if supported) :
- the lowest RAM bus speed installed in your computer is the one that is taken into account
- prefer having the same ones in each bank
- usually take RAM with more chips on it as more recent ones better integrated often work less efficiently (to compare to the fact that it is easier to address components more quickly when there are more places to split the search)
- and more than all be careful of latency (CAS) vs speed.
An interesting thing to know about RAM is that if your BIOS is up-to-date many old systems said to be limited to 8MB can often support 16 MB … which can provide a huge gain in performance.
Depending on your use also take into account the following metrics :
- RAM performance increased by let’s say x6 since DDR3
- NVME vs SATA SSD is also around x6 in performance
- dedicated GPUs can be usefull on certain cases
and what is coming next :
- PCI bus v5 that will make a huge increase on bus performance
- a wider use of DDR5
- the 2 next coming years will see another huge increase in overall performance that should be really deploying in … 2023.
- in the meantime, optimizing systems from previous generations keeps being a good way to lower costs.
SWI-Prolog having a smart use of multicore / muti-threaded processors, the more you have working at high speed, the quickest you should work.
What else ? I guess SWI-Prolog compiling tricks but this is software tricks … if some want to complement my post in comments …
EDIT-1: I forgot to mention that hardware doesn’t make it all as when programming … the performance is also coming from the developper. There are many ways to do the same thing taking more or less time … and this is the reason to benchmarking programs as calculation times can be measured in multiplying factors …
EDIT-2: To have a broader view of recycling useful, another use of old computers = make proxies under Linux with Squid and your internet will be here again much faster.