How does a 7 year old CPU compare with a 2 year old CPU?

Question

I'm running a 7 year old MacBook Pro (one of the first retina ones) as my main work PC. I pimped it out with 16GB RAM at the time and used it for video and photo editing for a few years before retiring it from that role, installing Windows 10 on it and using it as my main software dev machine. It's been working fine in that capacity, but is starting to slow a touch now.

So I'm looking to replace it with a new laptop, but I'm struggling to identify a replacement. Looking at the Thinkpad X1 Carbon and Surface Pro 6, they both have a i7-8650U in them, which cpubenchmark.net gives an 8824 mark to. However, the i7-3720QM in my MBP gets an 8127.

I'm not sure I want to shell out £2,000+ for a 9% increase in performance. I would guess that the RAM and SSD will also be faster these days, but I don't know for sure. Is it as simple as comparing the benchmarks? Is there more to it? What else do I need to take into account? Ultimately, how can I compare two laptops specs and get a handle on how they compare?

To be clear, as I've seen similar questions closed: I'm not looking for someone to tell me what to buy, I want to understand how to compare the specs myself.

Update: Seriously? Closed for this reason:

"Questions seeking for hardware shopping recommendations are off-topic because they are often relevant only to the question author at the time the question was asked and tend to become obsolete quickly. Instead of asking what to buy, try asking how to find out what suits your needs."

I'm not asking for buying advice, I'm asking "how to find out" how to compare hardware. I specifically mentioned this in my last paragraph to try to avoid the post being closed. The answers to this post could help other users seeking to understand how to navigate the minefield of comparing CPUs. Please consider re-opening the question, or at least provide a specific reason as to why it should be closed.

Answer 1

The problem is that while the processor itself might be only moderately faster there are too many other factors at play.

If the CPU benchmark you saw fits within the CPU cache it might show that the CPU core is not significantly faster but everything surrounding it could easily be a lot faster.

RAM has moved from DDR3 to DDR4 and is running at faster speeds, giving a performance boost that way.

SSDs have been steadily improving in speed and a new NVME SSD will absolutely dust a spinning rust HDD, and will still be somewhat better than an old SATA SSD.

Graphics processors, both discrete and built into your CPU, have also been improving both in terms of raw processing power and in terms of power efficiency. Many programs can also, depending on the task, use the GPU to do tasks such as processing video. Newer GPUs will support full hardware playback of modern video, thus saving your CPU for other tasks. Older GPUs will not support full hardware decoding, especially not of h.265 or newer video.

Being able to do more effective work using less power (or the same amount of power but in less time) can also result in an overall improvement in battery life.

There are other factors but these will easily make a newer machine faster at some jobs and at the very least much more responsive than an older machine.

You can't really just look at a CPU benchmark. You have to look at the system as a whole.