Page 1 of 1

SpeedStep Question

Posted: Thu Jan 17, 2008 8:33 pm
by Pocket Aces
I have a 2.0 GHz T7500. I usually keep it on the highest speed, through the ThinkVantage Power Manager. CPU-Z tells me that I'm running at 19** MHz at a 10x multiplier, which I assume is normal. However, when I switch to a power profile that uses the "lowest" setting under "Maximum CPU speed", the multiplier only drops to 8x, and the clock speed is at 1.6 GHz. That seems a little high for the "lowest" speed, doesn't it?

Posted: Thu Jan 17, 2008 11:51 pm
by SHoTTa35
are you still on AC power when you do that? If so then it will keep a higher clock, try unpluggin the machine and see from then.

Posted: Fri Jan 18, 2008 10:22 am
by Pocket Aces
I had thought of that. It only goes to 1.6GHz on battery power as well.

Posted: Fri Jan 18, 2008 10:39 am
by SHoTTa35
weird, your T7300 should drop down to 800mhz i guess but as you said it doesn't seem to go any lower.

My 2.0Ghz Core Duo only goes down to 1Ghz but i guess it only goes down to 800mhz if the BIOS supports it.

Posted: Fri Jan 18, 2008 11:21 am
by aaa
Random fact:
The minimum speed is 6 x FSB.

So there are minimum speeds of 600, 800, 1000, and 1200 for the various Intel processors. A 667-fsb processor like SHoTTa35's goes down to 1ghz. An 800-fsb processor like Pocket Aces' goes down to 1.2ghz.

As to why it won't go all the way down to 1.2 instead of 1.6, I'm not sure. Something to do with the IBM power management? Maybe the speed's not being read right?

Posted: Fri Jan 18, 2008 1:22 pm
by awolfe63
The T7500 drops to 800 MHz - but it does it by dropping the FSB to 100MHz (from 200MHz) and using a multiplier of 8x. Most of the CPU speed tools (including CPU-Z last time I checked) get it wrong.

Intel has a tool called Intel Thermal Analysis Tool that gets it right. MOBmeter does as well if you set it on "From Driver"

Posted: Fri Jan 18, 2008 4:36 pm
by Pocket Aces
Then I guess the problem is that the bus speed won't drop from 200MHz to 100MHz (unless CPU-Z is in fact giving me the wrong clock speed). However, I'm using Vista x64, so TAT doesn't work for me.

EDIT: Okay, I see now that the problem is CPU-Z. According to PC Wizard, it does indeed clock down to 800MHz. Thank you everyone!
I also have another concern involving CPU-Z. It's telling me that my memory is running at 333MHz, but I'm certain that I have PC-5300 memory. Is CPU-Z wrong again?

Posted: Fri Jan 18, 2008 5:18 pm
by awolfe63
333MHz X 8 byte wide memory X 2(DDR) = 5328MB/s - PC5300

Posted: Fri Jan 18, 2008 7:28 pm
by Pocket Aces
awolfe63 wrote:333MHz X 8 byte wide memory X 2(DDR) = 5328MB/s - PC5300
So when I hear that PC-5300 is clocked at 667 MHz, it's the frequency multiplied by 2(DDR)?

Posted: Fri Jan 18, 2008 10:20 pm
by awolfe63
Yep

Posted: Sat Jan 19, 2008 1:22 pm
by SHoTTa35
those PC ratings are all DDR (which is why i rather saying DDR333, DDR400, DDR667 - yes i know it's DDR2 667mhz) instead of PCXXXX. It's just crazy trying to figure out the actual speeds sometimes (even tho i memorized them all). Saying DDR also reminds ya that it's Double Data Rate so 333 x 2 (Double) would help you remember :)