Analysis of power usage in 10875H devices (XPS 9700)
Analysis of power usage in 10875H devices (XPS 9700)
Hello everyone, Just a brief informative thought about the power scaling of the newest Intel space heater. As many laptops users, I too want my battery to last for as long as possible. That's why I've been playing a lost in my XPS 9700's bios to try different things and get the power consumption down to as little as possible, while doing everyday tasks. Here are my findings: 1. On stock, system reports an idle consumption of around 8W, give or take (as reported by HWInfo64) 2. Disabling Turbo boost does not aid this (idle still at 8W system), but it does reduce performance by about 40% (from 3750 to 2050 CinebenchR20 score (calibrated, heat soaked)) - max power consumption drops from a theoretical 100W (75W sustained after re-paste, also max PL1 limit in ultra performance more) to just 27W (Cinebench R20 load). Temps drop from 100°C to around 50-55°C with fans barely spinning. 3. Manually adjusting PL2 and PL1 in XTU does not aid idle system power - but it's worth saying that CPU scales best up to 40W, after which performance gained per watt drops significantly. (Only around 25% for additional 35W or thereabouts) - limiting wattage for that alone is worth it in my opinion. Battery drain issue in heavy system loads doesn't help either. 4. When disabling 50% of the cores in bios (only 4 active), HWinfo64 reports an idle system power consumption of around 5W (4.6-5.3), which is a significant gain over the stock configuration. System responsiveness does not suffer, except in heavy multi-threaded applications. It's also worth mentioning that because there's more power budget to be had for less total cores, CPU still consumes around 65W on full load - boosting higher and for longer, since there's no temperature limit in place. (max sustained limit at around 75W). I haven't run CBR20, but I figure it must be around 2200. (compared to all 8 cores at base frequency achieving similar score at less than half the power, it really shows how bad the power scaling is higher frequency ranges) 5. Enabling just two cores does slow the system down significantly, loading times are longer, there's noticeable hang even while opening browser or office application. CBR20 score is just over 1100, at 47W CPU power (HWinfo64). This means that I can't recommend anybody to use the i7-10875H at this configuration. The good news though is that now, HWinfo64 only reports around 3-4W system power at idle. If you only do simple task on battery - this might be the way to go. Conclusion: For plugged in use, keep CPU fully unlocked and use ultra performance with PL1 @75W. If you do heavy system loads with GPU as well, manually limit the CPU to 35W or it WILL drain from the battery. Even in optimized mode, system still allows CPU to draw 45W, and that puts it above the 130W limit, even if not reported by HWinfo64. For office use and those, who try to achieve whole day battery, I recommend putting the system in Optimized mode, while only running 4 cores enabled. It will gain around 1 hour of usable time, since you now only use 10W on average instead of 12-13W. I hope this is useful to someone, feel free to correct me if I made any mistakes. Cheers