I upgraded from an Athlon II X3 435 to a Phenom II X6 1055T last year on my primary Windows 10 machine at home. I'm very pleased. This will last me years. This was a cheap upgrade since all I needed to do was update the BIOS and drop in the new (old) CPU. I had upgraded to 8 GB and SSD years ago, and that's all I need on this machine.
Note though this is used mainly just for business applications (including Office and VPN), mail, and surfing, with rare Netflix 1080p. The Athlon II 435 could do those tasks, but was a bit laggy at times, whereas I have no such complaints with the Phenom II 1055T. Also note though my other desktop sitting right beside it is a 5K 27" Mac with an i5 7600, so I do have a bit more power available to me if need be. I actually had an i7-7700K iMac first, but it was too loud under load, so I returned it and got the i5.
My main laptop is a MacBook Core m3-7Y32. I'm extremely pleased with that too. Silence is golden.
As you can see, not all of us need so much computing power.
Fast forward to May 2020 and I’m still on the same setup. I expect my Phenom II X6 1055T to last me at least another few years. Whereas the Athlon II X3 435 was a bit annoying at times, none of those annoyances exist with the Phenom II X6. I find it rather telling that many desktops in 2020 are being sold with performance benchmarks in the same ballpark as these chips.
BTW, in addition to the machines above, we’re using:
Core 2 Duo 2.0 GHz: 2008 aluminum MacBook in kitchen (macOS 10.13 High Sierra)
Core 2 Duo 2.26 GHz: 2009 aluminum MacBook Pro in guest room (macOS 10.13 High Sierra)
I also have a Core 2 Duo 2.4 GHz 2008 white MacBook with SSD and 4 GB RAM that I couldn’t install High Sierra on, so I converted it to Chrome OS. It works fine for that in terms of performance, but I have some WiFi flakiness which prevents it from being a true portable machine. It might be a compatibility issue with my multi-Airport Extreme setup, since WiFi works perfectly under OS X.
For the three Core 2 Duo machines, they are too slow for surfing if ads are allowed, but with AdBlock in Chrome, performance is fine. I’ve discovered that this particular browser and ad blocker combination has very good site compatibility.
OTOH, I have a Windows 10 laptop with Pentium SU4100 and 4 GB RAM, but even with SSD, that thing is basically unusable. Way, way too slow.
Geekbench 5 multi-core scores:
360: Pentium SU4100
530: Core 2 Duo 2.0 GHz P7350
600: Core 2 Duo 2.26 GHH P8400
660: Core 2 Duo 2.4 GHz T8300
1050: Athlon II X3 435
1650: Core m–7Y32
2000: Phenom II X6 1055T
3800: Core i5-7600
BTW, my wife’s iPad 7 10.2” gets about 1430, and my iPad Pro 10.5” gets about 2300. The iPad 7 is very decent for surfing, and my iPad Pro 10.5” is excellent IMO.
Thus in 2020, I think for entry level 1400+ is adequate, and 2000+ is good for a business user. So, for a mainstream business desktop, a Core i3-7100, which scores up to around 2400, would likely usually be sufficient, as long as it’s outfitted with 8-16 GB RAM and SSD. The Core i3-7100 also supports hardware h.265 decode and Netflix 4K streaming DRM (as long as the motherboard supports HDMI 2.0).