i5750 4 threads BEATS overclocked i7920 8 threads

[3DCGdesign]

This Core i5 750(2.67Ghz) (STOCK!) is still beating this Corei7 920 (2.67GHz & 3.61GHz)

Any idea why?

 

Shouldn't the i7 be min 2x faster?! The i5 beats it some of the time, OR if the i7 wins, it's only by a small margin in most cases.

 

I've oveclocked the i7 to 3.6, and it's steady and relatively cool (81*C max temp on Prime95)... but render times are not that greatly improved.

 

Two machines rendering same scene:

CPU	 Clock(GHz)	Cores	 Threads	  Scene		  Render Time (m:s)   "<-" signifies "winner"  
>>>Temps on i7o.c. never above 74* for these test<<<

i5		2.67 GHz	  4		  4		   A			 0:33
i7		2.67 Ghz	  4		  8		   A			 0:41
i7oc	  3.67 Ghz	  4		  8		   A			 0:30<-

i5		2.67 GHz	  4		  4		   B			 1:22<-
i7		2.67 Ghz	  4		  8		   B			 2:08
i7oc	  3.67 Ghz	  4		  8		   B			 1:30


i5		2.67 GHz	  4		  4		   C			 2:22<-
i7		2.67 Ghz	  4		  8		   C			 3:42
i7oc	  3.67 Ghz	  4		  8		   C			 2:44

i5		2.67 GHz	  4		  4		   D			 0:34
i7		2.67 Ghz	  4		  8		   D			 0:29
i7oc	  3.67 Ghz	  4		  8		   D			 0:19<-			 (this time is not even half the render time of the i5... I expected better)

i5		2.67 GHz	  4		  4		   E			 5:52
i7		2.67 Ghz	  4		  8		   E			 5:00
i7oc	  3.67 Ghz	  4		  8		   E			 4:29<--

Edited April 14, 2010 by 3DCGdesign

[Krieg1337]

Lol @ the last one. I5 got its butt whooped there. Btw, since when is 81C cool? What do you have on there, stock cooler?

 

Also, I see great improvement from overclocking. 1. 11 seconds, 2. 38 seconds, 3. 58 seconds, 4. 10 seconds, 5. 31 seconds.

 

To answer your question about how much faster it should be, no. Look at SLI or crossfire, your not getting 2x the performance gain. Things just don't work that way in computers.

[TheHippi]

Lol @ the last one. I5 got its butt whooped there. Btw, since when is 81C cool? What do you have on there, stock cooler?

 

Also, I see great improvement from overclocking. 1. 11 seconds, 2. 38 seconds, 3. 58 seconds, 4. 10 seconds, 5. 31 seconds.

 

To answer your question about how much faster it should be, no. Look at SLI or crossfire, your not getting 2x the performance gain. Things just don't work that way in computers.

Also, that program might not support 8 threads.

[3DCGdesign]

thanks for your thoughts.

It supports 8 threads and are running at 100%

 

Yes, there's improvement in overclocking, but why is the i5 beating the i7 at all? The stock i7's not even keeping up.

 

The Stock i7 2.66 should be slaughtering the i5 2.66... doesn't make any sense.

 

 

 

----off topic----

running Noctua D14, and it's MUCH cooler now than when I tried to o.c. on the stock cooler. (couldn't be done, actually)

I will improve air intake soon... but that's not the question in the topic. 80C is still a long way from tj=100C.

 

Besides I never hit more than 74C for these tests.

Edited April 14, 2010 by 3DCGdesign

[Krieg1337]

I'm sorry, I did not remember that the i7's are extremely hot when overclocked.(People cry about Fermi but not about the I7?) Anyways, i5 is also newer socket and newer technology. You should compare that i5 750 to an i7860(That is the current one on 1336 right? or is it the i7 930 now?).

 

The extra 4 cores are virtual, not physical. And again, you will never see a 100% increase by doubling something in computers.(SLI, Crossfire, memory ect. it just doesn't work)

[Praz]

What program is that. Supporting x number of cores and properly distributing the workload across the cores is not always the same thing.

[RJR]

I will improve air intake soon... but that's not the question in the topic. 80C is still a long way from tj=100C.

 

Besides I never hit more than 74C for these tests.

 

The way the program is coded will determine on what series processor is most efficient. Example: Super Pi likes the 9xx series, Y-cruncher likes the 8xx series.

 

The thermal spec for the 9xx series processors is 67.9c, you may want to download Intel's data sheet on you processors so you know what the recommended and max voltages and temperatures are. It is not recommended to run your processor over the thermal spec and to run a processor anywhere near the Tjmax is really not recommended and will degrade the chip rather quickly.

[road-runner]

The i7 could be throttling down, could be turbo is not holding. Check that all setting in the bios are equal. Then check with turbo throttle to see if it is throttling under load reducing speed, Asus boards are bad about throttling even with all the speed step and thermal stuff off. It could be throttling due to heat also if your up in the mid 80c temps also. Are all RAM settings the exact same, are all bios settings the same?

[Waco]

Hyperthreading could be hurting more than helping. Try turning it off on the i7 rig.

[3DCGdesign]

Thanks for the reply, guys.

 

hmm... will check it w/out hyperthreading.

 

I disabled turbo... it seemed to be causing more trouble than helping while testing the o.c.'s

Edited April 14, 2010 by 3DCGdesign

[3DCGdesign]

This is how the memory is set right now... do I need to change this for overclocking? if so, how?

[sdy284]

give ycruncher a try

http://forums.overclockersclub.com/index.p...t=0&start=0

(make sure you use the right version, read the thread)