Intel Speedstep + emulators

[kyuusaku]

I use a netbook with an Intel Atom as my primary computer and the more demanding emulators chug with the Speedstep technology. Basically what it does is vary the CPU's clock multiplier based on load. Under high load my CPU is 1.6 GHz, under low load it's 800 MHz.

XP with the power management setting "Always On" is supposed to keep the CPU at 1.6 GHz, it doesn't. Emulators which would otherwise run full speed under a 800 MHz CPU such as Nestopia and FCEU are fine, emulators such as Nintendulator which clearly need at least a GHz, aren't fine, but not from lack of processing power. You'd think such programs would throttle CPU usage really high, but in fact Nintendulator just stays around 55% (of 1.6 GHz) sporadically achieving 45-60 fps which is very annoying. I can overclock the CPU to 2 GHz without consequence, but this doesn't help, the CPU usage is approximately the same.

Unfortunately turning off Speedstep in the BIOS keeps the CPU at 800 MHz not 1.6 GHz (yeah, it'd seem they have it backwards...), so that's not the answer.

I believe what's going on is that Speedstep is breaking emulator time keeping, but I have no idea how to fix this (other than hope to find a hack to force the CPU to 1.6 GHz or use emulators which run under a constant 800 MHz.)

I wondered if anyone has any insight on the problem because this technology is probably here to stay and will affect more and more people as we switch to "green" systems.

[Near]

My Atom netbook goes up to 1.6GHz and stays there for apps that need it. Using an MSI Wind U100 variant. Almost sounds like the throttling mechanism is screwy with your system.

Don't really have any insight on how to get your processor to stay at 1.6GHz always ... maybe one of those software-based overclockers (an abundance on Linux, surely there's a Windows one that can work with the Wind?) plus speedstep disabled can do it?

[Jagasian]

I use a netbook with an Intel Atom as my primary computer and the more demanding emulators chug with the Speedstep technology. Basically what it does is vary the CPU's clock multiplier based on load. Under high load my CPU is 1.6 GHz, under low load it's 800 MHz.

XP with the power management setting "Always On" is supposed to keep the CPU at 1.6 GHz, it doesn't. Emulators which would otherwise run full speed under a 800 MHz CPU such as Nestopia and FCEU are fine, emulators such as Nintendulator which clearly need at least a GHz, aren't fine, but not from lack of processing power. You'd think such programs would throttle CPU usage really high, but in fact Nintendulator just stays around 55% (of 1.6 GHz) sporadically achieving 45-60 fps which is very annoying. I can overclock the CPU to 2 GHz without consequence, but this doesn't help, the CPU usage is approximately the same.

Unfortunately turning off Speedstep in the BIOS keeps the CPU at 800 MHz not 1.6 GHz (yeah, it'd seem they have it backwards...), so that's not the answer.

I believe what's going on is that Speedstep is breaking emulator time keeping, but I have no idea how to fix this (other than hope to find a hack to force the CPU to 1.6 GHz or use emulators which run under a constant 800 MHz.)

I wondered if anyone has any insight on the problem because this technology is probably here to stay and will affect more and more people as we switch to "green" systems.

I had a similar problem with FuhQuake (Quakeworld client) a few years ago. Dynamic frequency scaling of my laptop's CPU was screwing up the game's timing, and it turned out that the bug was due to how FuhQuake was coded. A small patch to FuhQuake fixed the problem. I'm not sure if my laptop's feature was called Speedstep or not... it was an IBM T30.

Maybe Nintendulator is determining how much CPU it should use before it starts to run, and so it sees your CPU as an 800mhz CPU. If so, it is more of a bug in Nintendulator than in your laptop.

[Dwedit]

I just use a program like RMClock to switch between Dynamic Switching, Max Battery and Max Performance.

[kyuusaku]

I'm also using a Wind U100, and while MSI's system control utility *is* very screwy it does what it's supposed to do (toggle the different functions).

I just tried RMClock but I don't notice any improvement and CPU-Z still shows the frequency switching back and forth. Maybe it can't override MSI and Windows' power management or perhaps it doesn't support throttling the Atom. I noticed it isn't in the list of supported processors and internet peoples are asking for support.