TDP & CPU question

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plympton
Posts: 229
Joined: Sun Mar 14, 2004 11:40 am

TDP & CPU question

Post by plympton » Fri Jun 05, 2009 10:12 am

I'm considering getting a new (used) laptop. I've got a Pentium-M Banias Thinkpad, and it undervolts really nicely in RMClock - down to .8v @ 600 MHz or so.

I'm considering getting an X60 or X60s - the only difference is the processor. An L2400 and a T2400.

From Intel, the differences are:

L2400 is a 15w TDP part, 1.0V - 1.212V, 1.66 GHz

T2400 is a 31w TDP part, 1.1625V - 1.30V, 1.83 GHz


From what I've experienced on a Core 2, you can't undervolt below .950v - hard lock, apparently, and I assume that I'll be able to get either down to that.

1. Does .09v @ 1.83 GHz really make for a 31w TDP part, or is Intel just being conservative?

2. Since machines are mostly at idle (web browsing), and assume I get either down to .95v, won't they use the same amount of power? (ie: not worth thinking about)

Essentially, an X60s will be guaranteed to run at what I might/probably will be able to get an X60 to run at, right?

Thanks!
-Dan

jessekopelman
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Joined: Tue Feb 13, 2007 7:28 pm
Location: USA

Post by jessekopelman » Fri Jun 05, 2009 2:21 pm

TDP is not the same as power consumption, especially using Intel's rating system.

I would say yes; that, comparing idle to idle, two chips of the same architecture are going to draw about the same, even if they have widely different TDP ratings.

plympton
Posts: 229
Joined: Sun Mar 14, 2004 11:40 am

Post by plympton » Fri Jun 05, 2009 9:26 pm

That's what I thought. I realize that TDP is a black art / black box / whatever, and I'm sure they "batch" TDP the chips - the 2.4 GHz has the same TDP as the 1.6 GHz chips in a family, which doesn't make sense to me at all logically. Sounds like "worst case scenario" type of stuff.

-Dan

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