[Solved] Baffled

[at both ends]

I have a T420 with an i3-2310m inside. CPU is marked as (capable of) running at 2.1GHz. 8GB RAM and an Intel SSD make it plenty fast. Not a gamer so I don't really care about video specs.

Anyway, I ran the standard passmark test suite and was floored by the CPU results. The overall result is a 1073 on the CPU, whereas a generic i3-2310m should go 2760. So I started looking around, downloaded a copy of CPU-Z and CoreTemp, ran them both, and they show the CPU frequency nailed at 800MHz, no matter what's happening. That includes running the passmark suite and an extended run at what's called the Intel Burn Test, which is a multi-threaded floating point heavy CPU workout.

Since 2100/800 is near enough the same ratio as 2760/1073, I'm more than a little suspicious that the passmark rating on my T420 is caused directly by the CPU never clocking up. What I would like to know is why that never happens. I fiddled in the BIOS with turning Speedstep on and off but that made no difference that I could see.

Thanks in advance for an explanation, or even a pointer to where I should look next.

[AIX]

I'd check in Power Manager the setting for System performance to not be Low but Balanced. Or if you do not have Leonovo's Power Manager installed, check Windows' Power Options > Advanced Settings > Processor power management > Maximum processor state - and be sure it's 100%, at least on AC power.

[at both ends]

I fiddled with Power Manager before I started, setting everything to Max Performance. Still, in the basic view, the CPU is shown as running at 38%, which about tallies with what I see out of the benchmarks.

The throttling has no visible effect on what I do with the T420. As I said, it's a peppy machine on the default settings. It runs cool - typically around 40C on the CPU - and quiet - fan either off or about 2000rpm and barely audible. I would just like to know why the CPU is throttled like this so, if I'm in a situation where I need some oomph, I know that I will get it automatically and not have to go hunting for a tweak somewhere.

[at both ends]

The issue is described succinctly at http://forums.lenovo.com/t5/X-Series-Th ... a-p/545661.

I routinely run the machine with battery out. Rerunning the benchmarks with battery in results in "normal" performance. WEI score up a lot too.

What a bizarre thing, when a laptop runs faster on the battery than when plugged into the wall.