How powerful a CPU do I need?

[clv101]

I haven't bought a desktop CPU or system for 13 years. Not since my Core 2 Duo E4300 1.8GHz, overclocked to 3.2GHz. For the last decade I've been exclusively running MacBook Pros and in the last few months a ChromeBook. I'm now in the market for a modest, low power consumption desktop but unclear exactly where to dive in. The CPU world seems a lot more complex than it used to be!

My personal points of reference are few, looking at cpubenchmark.net:

My old E4300 (similar to an E6850) 65W single thread rating 1187, CPU Mark 1124
My 2012 MPB has the i7-3615QM 45W single thread rating 1680, CPU Mark 5030

I'm initially drawn to the Ryzen 7 4800U 15W single thread rating, 2633, CPU Mark 17546.

The Ryzen looks good compared to what I'm used to. Much more performance for a lot less energy. What's the catch? It even seems to have half decent graphics built in. I'm quite tempted by the recently announced Asus PN50, seems like a tiny box with great performance - just no opportunity for external GPU.

Questions:
How capable is the 4800U's GPU? Can it actually cope with modern games at 1080p?
Is it possible to buy a Ryzen 7 4800U system with potential to add a PCIe GPU?
What's the advantage in going up to the 65W desktop processors with all their extra heat, energy, size and noise?

I think what I really want is very small desktop based around the 4800U with a single slot for an external GPU, does such a thing exist?

Should add, this will be a Windows 10 'family' PC. Used for web, office, photo editing, streaming and (potentially) light gaming.

 

[clv101]

For 1080p gaming you really need a minimum of a RX 570/580, the 4000 series APUs can do it, but like said above, this is with everything on low. If you're willing to stick with old games, especially DirectX 9, then it is more realistic.

It sounds like you want an ITX PC.

Yes, that's a good point. If I want more graphics performance than the 4000 series APUs I need an external card. That leaves me thinking, that if I'm going down the external GPU route, do the new Ryzen 7 APUs still make sense? Would I be better off without the integrated GPU?

What does the external GPU do to power consumption - when just on the web for example, not gaming? Do they have a large power consumption overhead compared to integrated GPUs?

I'm liking the idea of the recently announced Ryzen 7 4700GE, ups the TDP to 35W in exchange for higher frequencies. It sounds like these new Ryzen 7 chips are only going to be available to OEM system builders like Lenovo and HP initially though. I'm probably okay with that though, the Lenovo ThinkCenter M75s looks like a nice machine. A bit more potential compared to something like the Asus PN50 4800U machine.

 

[clv101]

I'm keen to get the power consumption down as low as possible (house is off-grid, 100% self sufficient in energy).

 

[clv101]

Indeed, and we've been exclusively laptops for a decade. The stimulus for this is to have a fixed 'family computer' for children to use. Not too keen on the 5 yr old having free use my MBP!