Core i7 920 = 1.6 GHz?

[FordGT90Concept]

I wrote an app (attached) which detects the core speed for all cores in the computer it runs on and then graphs the speeds to monitor it for changes. It has worked correctly on a Pentium 4 w/ HT, a Pentium dual core, Opteron 180, and Xeon 5310; however, this app, and every other app I try on this computer, it always returns a speed of 1.6 GHz. It might be SpeedStep but even when I put 100% load on the processor, the clock remains at 1.6 GHz.

I can't figure out what's wrong.


It requires .NET 2.0 to run.

 

[ShogoXT]

What if you turn hyperthreading off?

 

[FordGT90Concept]

I just turned Hyperthreading off. Now we have...

0|1597
1|1597
2|1596
3|1597

The reported speeds are unaffected (except 4 cores are now gone). I'll try disabling EIST next.

Edit: EIST disabled, Hyperthreading back on:

0|1597
1|1597
2|1597
3|1597
4|1597
5|1597
6|1597
7|1597

Can anyone else with a Core i7 verify that this is normal? I wonder if I got a bad CPU. In any case, this is very odd.

 

[human_error]

Just tested on my core i7 920 overclocked to 3.7ghz with speedstep and power saving options fully enabled (ht on as well)

the app is not reading the full speed, it's stopped at 3500mhz, but is a lot higher than what yours is reading - does cpu-z show the low speed for you?

 

[FordGT90Concept]

The values I'm reading are the same values Windows uses (attached). If Windows is wrong then you'd think there would be pretty severe consequences relating to thread prioritization and the like. I also tried the timestamp approach to calculate the clockspeed which returned the same figure (1597 MHz). I tried this application and it also returns 1597 MHz. The only thing not reporting 1597 MHz is CPU-Z 1.50 (2.776 GHz, 21 * 133 MHz). I'm convinced CPU-Z is wrong and the other three sources are right.


The difference between 3.5 GHz and 3.7 GHz could be Turbo (20x vs 21x). The value the app shows is the value Windows has. But since it is reporting the speed you expect it to be, that again points the arrow at my processor/motherboard, something not right.


The 1.6 GHz could be coming from the FSB speed * 3 (533 * 3 = 1599). Why it would be reporting that as the CPU speed doesn't make any sense though.

 

[thraxed]

Yeah thats not right, every version of windows has detected my cpu speed right. Maybe ya have something set wrong in your bios?

 

[FordGT90Concept]

Almost all the BIOS settings are default except SATA/RAID and max CPU temp. Which setting would it be?

Edit: I updated the BIOS to the most recent and everything is still saying 1.6 GHz.

 

[FordGT90Concept]

Just tested on my core i7 920 overclocked to 3.7ghz with speedstep and power saving options fully enabled (ht on as well)

Has the app showed the clockspeeds change when SpeedSteps kick on and off? That's really the main reason why I came across the 1.6 GHz issue.

 

[blastboy]

Speedstep off everything stock...reads all 8 @2672 fsb1336

 

[FordGT90Concept]

Speedstep off everything stock...reads all 8 @2672 fsb1336

So clearly, the app is good but something in my system is not. Hmm, what would be a good benchmark to test if the CPU is processing data as it should? It's not right that it is reporting 1.6 GHz everywhere but as long as it is churring out the work of it clocked at 2.666-2.793 GHz, I guess it really doesn't matter. It just means I can't test that application.

 

[human_error]

Has the app showed the clockspeeds change when SpeedSteps kick on and off? That's really the main reason why I came across the 1.6 GHz issue.

No it doesn't account for speedstep changes, the displayed speed remains the same, also the speed it shows for my proc isn't even what it would be with speedstep off, it's close but about 1.8x multi off the actual speed, but still it's a lot closer to the actual speed than it is in your system.

So clearly, the app is good but something in my system is not. Hmm, what would be a good benchmark to test if the CPU is processing data as it should? It's not right that it is reporting 1.6 GHz everywhere but as long as it is churring out the work of it clocked at 2.666-2.793 GHz, I guess it really doesn't matter. It just means I can't test that application.

wprime - if the time on a 32m run is higher than 10 seconds (it should be less, i get 7.1 seconds at 3.7ghz with loads of background stuff running) then you have a problem.

 

[Mussels]

Yeah thats not right, every version of windows has detected my cpu speed right. Maybe ya have something set wrong in your bios?

not always. if i changed my multiplier below its maximum (lets say 400*8 for 3.2GHz), windows (and some software) would always read it as 400x9 (3.6Ghz)

 

[FordGT90Concept]

wprime - if the time on a 32m run is higher than 10 seconds (it should be less, i get 7.1 seconds at 3.7ghz with loads of background stuff running) then you have a problem.

OMGWTFBBQ! :|

I saw 50% numbers flash (they were 5-6 sec) and then bang, powered off. WTF!?! I disabled system restart on failure and going to try running it again.


Edit: I changed the power off temp from 65C to 75C and this is what it says:

32M - 10.406 sec (1596.4 MHz Bloomfield)

Another run:

32M - 10.578 sec (1596.4 MHz Bloomfield)

So it is performing on par but everything detects the speed (except CPU-Z) at a much lower clock. How odd.

 

[FordGT90Concept]

Ah, I finally figured it out. In my "Genie BIOS" it had Turbo mode enabled and the last of the Turbo options was a "non-turbo multiplier." It was set to 12 and 12 * 133 = 1596 MHz which Windows was reporting. I changed it to 20, disabled Turbo mode, and now Windows is reporting the correct speed of 2.66 GHz.


Still, I don't think I can fix that application of mine unless I wanted to spend $1200 to buy CPU-Z source code.

 

[FNoob]

920 speed at 1600...

I was alarmed to see the same thing in CPUZ at first. But, later I noted some sort of cycling is going on, and if I sat there and watched it, it would go from 1600 up to 2600 randomly, showing multiplier changes as well. It's normal, methinks. My understanding of Turbo mode was that it would increase the speed above 2600 - not below it. Isn't that anti-Turbo?