Semi-scientific battery test: 2 core 7600U vs 4 core 1145G7

[mikemex]

Hi guys. I recently got an X1C9 and I've been testing it. My first impression was that the battery life is shorter than my older X1C5 but I just wanted to see if that's really the case or it's just my prejudice.

X1C5:
7600U, 16GB, FHD, 1TB PC711, Windows 10

X1C9:
1145G7, 16GB, WUXGA, 256GB BG5, Windows 11

* Both on minimum brightness, muted sound.
* Only WIFI on.

I closed all applications, fired up:
* Edge, with a StarWars cinematic intro off Youtube.
* Lenovo Vantage (to monitor power consumption).

With the mouse over the Edge icon for a peek view, I keep watching videos and I found that:

* Performing the same task, both machines consume about the same power (5.5w).
* 7600U is very consistent about power usage.
* 1145G7 fluctuates a lot more, with peak power usage often higher than the 7600U (I seen as high as 6.9W).
* The X1C9 goes to a much lower idle power state (I've seen as low as 1.5 W).
* I've never seen the X1C5 go lower than about 2.5W.

Conclusion:

Both 7600U and 1145G7 use the same Skylake cores, so it's not surprising they consume about the same power doing the same tasks. The 1145G7 is more optimized as a whole, though. The reason the 1145G7 often performs poorly, is not the efficiency of the chip itself, but that it's allowed to do more work and therefore, suck more power. The aren't really magic tricks to make a Skylake core consume less power doing the same amount of work, but the jump from 2 cores to 4, allows them to perform the same tasks at a lower frequency, where they can do it more efficiently (which explains people's preference for X1C6 over X1C5).

The 1145G7 chip seems to respond really well to adjusting the Power Limits (PLx) via ThrottleStop. So if you need more battery life out of your 11th generation CPU, I'd suggest adjusting them to a low value. So far, I think the X1C9 may even bring more battery life than the X1C5 if properly configured to avoid the aggressive turbo settings it uses as default.

[mikemex]

It's official: I'm a ludite that quickly judges based on prejudice.

Meaning, Tiger Lake is more efficient power-wise than Kaby Lake.

I've never seen my X1C5 idle below about 2.7w. That's 21 hour idle time with its 57Wh battery.

With some tweaking to de-bloat Windows 11, leading to a C0 core usage average of 3%, my X1C9 can idle at 2.0w for a whopping 29 hours of idle time (actual battery capacity is 59Wh). I'm looking at an estimate of 12 hours and 47 minutes with 44% of charge remaining.

Quick tip:

If you want better battery life out of recent intel models, reduce the power limits (I use ThrottleStop).
All my tests were done using a 9w PL1 and 15W PL2 turbo configuration.
With that configuration, the fan stays always off, which can be significant at the lower end of the scale.
I'm not even on the lowest screen setting. I'm on the third level from the bottom.

I'm going to try to do the same tests with the 1365U Yoga.