SU7300: "Locked" Multiplier?

[rpg]

First off, this is a mobile CPU, specs here. It's an ultra low voltage CPU clocked at 1.3GHz with a FSB of 800MHz. So therefore it's multi is 6.5x, confirmed here.

I know of two laptops that these CPU's are fitted to; one is the Asus UL50Vt and the other is the Alienware M11x.

Both come from the factory with the possibility of utilising an "Overclock" mode, raising the bus speed to 266MHz and therefore the CPU speed, to 1.73GHz.

However, for some reason the Asus has a multi of 6.5x, but the M11x has a multi of 6x (obviously reducing it's CPU speed to 1.6GHz). I notice it's Vcore is also lower. Asus (below left), M11x (below right).

I've also read up on the SU7300 and it supposedly has two P-states; a 4x multi and a 6.5x multi. So how can the M11x have a multi of 6x? Do Alienware have a way to adjust/decrease the multi in the BIOS? The reason I ask is because I thought Intel lock the CPU multiplier on all chips (excluding extreme editions).

I originally thought it was Speedstep doing it to the M11x, but if it has only two P-states of 4x and 6.5x, how could it run at 6x? I'm looking to buy the M11x but one of the main reasons for buying it was it's ability to clock to 1.73GHz. I know it's only 133MHz less, but it's low enough as it is!

Am I missing something simple, or misunderstanding something? Any info appreciated.

 

[rpg]

Just to confirm, when I said "I thought it was Speedstep doing it", the reviewer of the M11x (where the screenshot came from) explained that all benchmarking tests were done with Speedstep disabled.

Also, I checked Wikipedia and it states the default voltage of the SU7300 is "1.05-1.15 V". So with Speedstep disabled, why is it running at 0.90v?

 

[Geckovich]

Intel multis are upwardly locked, you can still lower them. Not sure why alienware of all companies would downclock though.

 

[rpg]

Intel multis are upwardly locked, you can still lower them. Not sure why alienware of all companies would downclock though.

Ah, thanks Geckovich, that clears up one aspect of it.

I don't know either, quite confusing to be honest. You probably noticed the voltage difference, I'm wondering now if they undervolted the M11x's SU7300 to get more battery life, but reduced the multi to 6x to make it more stable while overclocked.

Another concern is that if they permanently lowered the multi to 6x, even in non-OC mode it will run the CPU at 1.2GHz - 100MHz less than it's advertised speed.

 

[hiroofheroes]

A lot of bios need to have half multis enabled - if the options turned off it would drop down to the closest whole multi.

 

[rpg]

A lot of bios need to have half multis enabled - if the options turned off it would drop down to the closest whole multi.

That's interesting. But being an Alienware machine, surely they'd be using a custom BIOS that could enable pretty much what they wanted?

It just seems that the above modifications to the configuration of the CPU was on purpose. It's only a new machine so maybe we'll hear more about it in due course.