Question i5-8350U or i7-8650U In Lenovo X1-Carbon Gen 6 ?

[Regev]

So,

I have the chance to buy a refurbished X1 Carbon with:

i5-8350U + 8GB RAM - $298
i5-8350U + 16GB RAM - $385
i7-8650U + 16GB RAM - $460

Which one would you personally go for ?

As far as I've read, both CPUs are nearly identical, 4c/8t, but with these two differences in favor of the i7:

Cache: 8 vs 6 (Mb)
Clocks: 1.9/4.2 vs 1.7/3.6 (Ghz)

My question:

Does it even matter on such a slim, lightweight laptop?

I found out these comments from people with Lenovo T480s:

"i7 is definitely not worth it. I had a i5-8350 and an i7-8650 T480S. The i7 ran hotter and actually performed a little worse under full CPU load for extended periods."

"I have T480s with i7. Not worth it at all. This design can't cool it. Stick to i5"

"I recommend the i5-8250u and undervolt+disable power limit to get about the same performance as the top end i7-8650u without the heat. If you want anything more, go no further than the i5-8350u, since it has more performance stock than the i7-8550u."

The 480s is thicker than the X1 Carbon, so I'd assume their points to be even more valid on the X1 carbon?

Would appreciate your advice.

Thanks

 

[Lutfij]

Personally, the last option, provided the laptop isn't damaged in any way, considering you did state that the laptops are refurbished units. Also, that last lsiting;
i5-8650U + 16GB RAM - $460 should be i7-8650U + 16GB RAM - $460

I found out these comments from people with Lenovo T480s
Source of these...comments?

On the matter of heat/cooling you might want to dig into ThrottleStop and consider undervolting the processor and the iGPU to aid in lowering the power draw and temps of the processor, considering that you're working with an 8th Gen Intel mobile processor.

 

[Regev]

Personally, the last option, provided the laptop isn't damaged in any way, considering you did state that the laptops are refurbished units. Also, that last lsiting;
i5-8650U + 16GB RAM - $460 should be i7-8650U + 16GB RAM - $460

I found out these comments from people with Lenovo T480s
Source of these...comments?

On the matter of heat/cooling you might want to dig into ThrottleStop and consider undervolting the processor and the iGPU to aid in lowering the power draw and temps of the processor, considering that you're working with an 8th Gen Intel mobile processor.

Thanks for the quick, elaborate reply. Much appreciated.

Did you pick the last option (nice catch regarding the typo, btw) because of resale value, or because of measurable, documented performance differences?

As for ThrottleStop, I did read about it, is this something I'd have to do anyway (even on the 8350), or only for the i7 to reduce heat? Also, is this something I can do once and it changes the BIOS settings and I can just forget about it? Because it runs on Windows, and I'm wiping the SSD clean to install Fedora.

Thanks again.

 

[Lutfij]

because of resale value, or because of measurable, documented performance differences?
Neither. The amount of hardware(with what limited info you've provided since a laptop needs more than just a processor and ram to operate) you're paying for the money.

It's a software that only works when in the OS GUI, no it doesn't alter the BIOS in any way.

 

[Regev]

because of resale value, or because of measurable, documented performance differences?
Neither. The amount of hardware(with what limited info you've provided since a laptop needs more than just a processor and ram to operate) you're paying for the money.

It's a software that only works when in the OS GUI, no it doesn't alter the BIOS in any way.

Everything else (hardware-wise) is 100% identical between the two. So, you mean that the extra cache and higher clocks are worth the $75 differences, and won't cause any additional heat/shorter battery, etc ?

As for the ThrottleStop, so if I change the settings there, and use Fedora day to day, the changes won't even apply? is there any workaround to apply the changes in Linux ?

 

[Regev]

Source of these...comments?

View: https://www.reddit.com/r/thinkpad/comments/aozo46/differences_between_i5_and_i7_for_t480s_and_x1/

 

[Lutfij]

won't cause any additional heat/shorter battery, etc ?
You might want to understand that as time moves forward and app's are updated, they tend to tax a little more from the system. So a slightly higher heat output can happen. You're working with a processor that's 5 Generations old(at this point). The battery? You don't expect the battery to be brand new, now do you? I certainly don't, meaning that battery life will be negligible when thinking of buying a laptop that's about as old as the 8th Gen processor now.

 

[Regev]

@Lutfij Alright, guess I'll be taking the i7. Just for final clarification, you're saying the extra 2mb of cache and higher clocks of the i7 will have an effect on the X1 Carbon, and that my assumption that they'll both throttle anyway (due to the slim case) and settle on the same performance is wrong?

Thanks again for your generous help <3

 

[Lutfij]

Just make sure you've got the back end of the laptop elevated using an eraser or a small book to have the laptop at a slight angle atop of your desk/table. This will aid in cooler ambient air flowing into the fan for the laptop. You could also try and remove the thermal paste in the laptop and reapply thermal paste of a higher pedigree like Noctua, Arctic or Thermal Grizzly. You can also replace thermal pads if you so choose with higher spec'd pads.

Following that, you can use ThrottleStop to undervolt the CPU's core and cache, the the CPU's iGPU.

Together with the three steps mentioned above, you should be able to deal with the temps to a better threshold.