Question about turbo mode

[red930]

I was thinking of overclocking my core i7 CPU 920, I have a question on turbo mode.

 

My defualt multiplier is 20. So 133 x 20 = 2.66Ghz, my advertised clock speed. And so when the CPU is really stressed my computer ups the multiplier to 21 and so I can go 133 x 20 = 2.79 GHz. So I can already acheive 2.79Ghz right out of the box? Why doesn't intel advertise the i7 920 as 2.79Ghz since it acheives those speeds under heavy load anyway?

[road-runner]

I was thinking of overclocking my core i7 CPU 920, I have a question on turbo mode.

 

My defualt multiplier is 20. So 133 x 20 = 2.66Ghz, my advertised clock speed. And so when the CPU is really stressed my computer ups the multiplier to 21 and so I can go 133 x 20 = 2.79 GHz. So I can already acheive 2.79Ghz right out of the box? Why doesn't intel advertise the i7 920 as 2.79Ghz since it acheives those speeds under heavy load anyway?

 

Under heavy loads and with some motherboards it will reduce from turbo mode to the lower multi to reduce heat. Asus is bad about turbo throttling (wont stay locked on 21), had the same problem with foxconn flaming blade.

Edited April 19, 2010 by road-runner

[red930]

Under heavy loads and with some motherboards it will reduce from turbo mode to the lower multi to reduce heat. Asus is bad about turbo throttling (wont stay locked on 21), had the same problem with foxconn flaming blade.

 

 

So what happens if you overclock to a stable 3.2Ghz with a 20x multiplier, but when turbo mode springs into action you destablize at 21x -> 3.35Ghz. Is the general recommendation to disable turbo mode and just OC to 3.2 with a 20x, and so not allowing your CPU to destablize at 21x?

[dling]

Most people keep it at the x21 mulitplier because the 920's seem to run better

at odd numbers. 17,19, 21. You can lock it down so it will stay at the speed you

set it at.

[wevsspot]

From another thread on a similar topic;

http://forums.overclockersclub.com/index.p...=174730&hl=

 

I did some extensive testing tonight with an i7 920 on an ASRock X58 Extreme board. I'll spare you guys all of the boring numbers........ But I can tell you unequivocally that performance was better practically across the board running the BCLK at 185 with a hard set multiplier at 20 than any combination of turbo enabled/disabled, CState enabled/disabled (strange thing on this board - you only get the 22 multiplier if CState is enabled). All performance tests ran using Everest and 3DVantage.

 

				 172*21 turbo off	  172*auto turbo on	  172*22 cstate on	  172*21 cstate off	  185*20 turbo&cstate off
cpu queen		30207				 30211				  30202				 not tested			 30969

cpu photoworxx   43800				 43829				  43799				 not tested			 42196

cpu zlib		 122672				122503				 122661				not tested			 124136

cpu aes		  28837				 28912		 		 28905				 not tested			 29622

 

 

Now you may be wondering why I didn't run the tests with cstate off - but as I mentioned on this particular board you have to enable cstate in order to get the x22 multiplier. The performance numbers obviously weren't going to get any better by losing the x22 multiplier.

 

Of particular interest would be the performance numbers between the 185*20 hard set (= 3.70Ghz) versus the 172*22 cstate on (=3.78Ghz). All tests were ran with HT enabled, Intel Virtual Technology Enabled, Thermal Throttling Off. Intel Speed Step was enabled for all tests.

 

3DMark Vantage CPU Score @ 185*20 hard set (22943)

3DMark Vantage CPU Score @ 172*22 cstate on (22332)

 

Anyways, based on my testing the rig will run @ 185*20 hard set with Speed Step enabled. P.S. this is at 1.20vcore

 

The one abnormality in the testing was the photoworxx test scores where the performance was worse. I reran the test five times and the results were conclusive......?

Edited April 19, 2010 by wevsspot

[hardnrg]

some motherboards can keep the multiplier at 21x all the time, regardless of load... this is what will get you the highest OC

[wevsspot]

some motherboards can keep the multiplier at 21x all the time, regardless of load... this is what will get you the highest OC

True - on the ASRock X58 Extreme, once you enable Turbo Mode once, then the x21 multiplier option remains even if you disable turbo mode. The only reason I'm not using the x21 multiplier is that we are fixing to move into the summer months in my neck of woods, and I'm perfectly happy at 3.7Ghz and reasonable temps

[hardnrg]

well, if you are settling for 3.7, how about 19x195=3705? It might be able to run on even less voltage(s)... and I would expect you could maybe get a better OC, for the same CPU voltage, using the 19x instead of 20x

[fish1717]

<!--quoteo(post=1802898:date=Apr 19 2010, 12:58 PM:name=hardnrg)--><div class='quotetop'>QUOTE (hardnrg @ Apr 19 2010, 12:58 PM) <a href="index.php?act=findpost&pid=1802898"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->some motherboards can keep the multiplier at 21x all the time, regardless of load... this is what will get you the highest OC<!--QuoteEnd--></div><!--QuoteEEnd-->

True - on the ASRock X58 Extreme, once you enable Turbo Mode once, then the x21 multiplier option remains even if you disable turbo mode. The only reason I'm not using the x21 multiplier is that we are fixing to move into the summer months in my neck of woods, and I'm perfectly happy at 3.7Ghz and reasonable temps <img src="http://forums.overclockersclub.com/public/style_emoticons/<#EMO_DIR#>/smile.gif" style="vertical-align:middle" emoid="" border="0" alt="smile.gif" />

 

I've tried enabling Intel Speed Steep and Turbo, but my multiplier is still locked to a max of 20. You can actually change the multiplier to 21 in the bios? What bios version do u have ?

[wevsspot]

I've tried enabling Intel Speed Steep and Turbo, but my multiplier is still locked to a max of 20. You can actually change the multiplier to 21 in the bios? What bios version do u have ?

 

I'm running version 1.90 on the ASRock board (or I should say was). Board was sold to fellow forum member this week

As soon as I enabled Turbo Mode one time the x21 multiplier became available as an option regardless of whether I had Turbo Mode enabled or not.

 

Harding made a good point though about hard setting a lower multiplier and upping the bclk. As you up the bclk the X58 boards really start to spread their wings so to speak.