i720QM - Wont Turbo

AmDaMan · 13 Nov 2012 at 09:24

Hi chaps,

Just bought a 2nd hand laptop and it has a 1st gen i7 720qm 1.6x4. It's supposed to go to 2.6 or something under load but it just refuses to! The only way I can get it to exceed 1.6ghz is to use throttlestop and force the turbo..

The laptop is still fairly fast but it's just annoying! I've changed the powerplan, checked the temps, latest chipset drivers etc but nothing seems to work. It has the latest BIOS but it doesn't have any options in there.

Is there something I should be doing or is this just the way it is?

Cheers

unclewebb · 14 Nov 2012 at 06:01

The Core i7-720QM has a default speed of 1.60 GHz. The amount of Turbo Boost these CPUs can use depends on how many cores are active.

Code:

1 core  - 2.80 GHz - 21 multiplier
2 cores - 2.40 GHz - 18 multiplier
3 cores - 1.73 GHz - 13 multiplier
4 cores - 1.73 GHz - 13 multiplier

These are the maximums. The amount of Turbo Boost can be limited by power consumption (TDP), the amount of current flowing through your CPU (TDC) or the core temperature. It's usually power consumption that limits Turbo Boost.

When fully loaded with something like Prime95, power consumption will exceed the Turbo Boost power limit and so Turbo Boost gets completely turned off leaving your CPU running at the default 12 multiplier or 1600 MHz.

For Turbo Boost to fully work, you need to make sure the C3 and C6 sleep states are enabled. unused Cores need to be able to enter one of these sleep states so the remaining active cores can Turbo Boost up to the higher multiplier.

The Turbo TDP and TDC power limits are locked in these processors so they are kind of lame. Their big brother the Core i7-920XM Extreme CPU can run fully loaded over 100% faster than the 720QM. If you can keep a 920XM cool enough, they can run all 4 cores fully loaded with a 24 or 25 multiplier compared to the 12 that you will get when your 720QM is fully loaded. Big difference. Time to start saving up. You won't be disappointed.

To better understand how these CPUs work, download ThrottleStop.

ThrottleStop 5.00
http://www.techinferno.com/downloads/

It's a very good monitoring tool for these CPUs and can accurately calculate just how much Turbo Boost you are really getting during normal use. You can turn on the Log File option and go do some gaming and then when you are done you will have a record of what multiplier your CPU was using. It varies hundreds of times a second. ThrottleStop uses high performance timers within the CPU to calculate an average multiplier while this is going on.

The sad part is that Windows background tasks often keep 2 or more cores active so you will never see the full 21 multiplier unless you disable 3 of your 4 cores which isn't a very practical thing to do to a Quad.

AmDaMan · 14 Nov 2012 at 08:43

That's a very good explanation, thanks!

I had a look at the 920XM and it looks like a beast, it's still fetching about 200 quid though. Is it worth me buying it or should buy a new laptop?

I doubt it will be that cool in a laptop though which could be an issue but 4 cores at 2.6ghz sounds like a hoot!

matthab · 14 Nov 2012 at 12:36

Well is your current laptop not performing because of the CPU holding you back?

Id say just live with it, it should be ok for most uses.

unclewebb · 14 Nov 2012 at 17:06

AmDaMan said:
... but 4 cores at 2.6ghz sounds like a hoot!

I don't think you fully understand just how beastly the 920XM really is. Maybe this will open your eyes. :eek:

svl7 over at Tech|Inferno knows how to get the most out of a 920XM. Yes, this is definitely a laptop and all 4 cores are fully loaded. This is a whole different performance league compared to what a fully loaded 720QM can run at.

AmDaMan · 15 Nov 2012 at 03:38

Matt - The 720 isn't bad. I'm looking to buy a couple of games in the future so that will probably test it more. General OS tasks are fine though. I just like having fast things I guess..

:eek:

that looks serious!! That looks like a desktop version though with some serious cooling? A laptop might be harder to get me most out of? Can you select the turbo multipliers using throttlestop with the 920XM??

200quid seems like a bit of a bargain when i see that.. are there 2nd and 3rd gen i7's that have that capability? The only issue is this motherboard has the PM55 chipset so a bit old now, so things like sata3 and usb3 are missing etc. Not sure weather to buy a new laptop or just beast this one up.