Hi there. newbie question please. I'm running rosetta@home on several dedicated computers for a couple of weeks now. Computers in question are more or less identical, Dell computers from 2010. Both running W10 pro 64bit, both have SSD's with plenty of free space. both are running with 100% CPU and time allocation. One is 4GB RAM and i3-380M, the second one is 8GB RAM and i7-720QM processor. For two straight weeks both produced a similar amount of credits ( 11,600 on i7 and 11.400 on i3). RAC is 590 on i7 and 625on i3. results are 484 on i7 and 141 on i3. From this data it looks like 4cores of I3-380M are doing a better job than 8 cores of I7-720QM. it doesn't make any sense to me. Can anyone explain please why i7 CPU is performing so poorly?

Sincerely, Sarah

When you talk about the RAC of the two machines, then talk about the "results", are you counting the number of tasks? Or talking about current RAC figures?

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Rosetta Moderator: Mod.Sense

I see you have many machines registered. Which two are you asking about? (host ID numbers)

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Rosetta Moderator: Mod.Sense

If you are looking at your list of hosts and the "results" column, this is just the current number of active and completed tasks on file. But they are purged with age. So granted credits and RAC are more concrete measures.

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Rosetta Moderator: Mod.Sense

This seems to be a particularly early I7, rated at less than half the speed of my AMD FX-8120, but if it's Host ID 2497488 it does seem to be particularly slow going by the Int and FP measures showing. The I3 looks about what I'd expect

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i did a quick comparison here
http://ark.intel.com/compare/50178,43122

some differences become quite apparent

i3-380M         i7-720QM 
2.53 GHz        1.6 GHz
32 nm 	        45 nm
DDR3 800/1066   DDR3 1066/1333
2 core          4 core
4 threads       8 threads
No Turbo Boost 	Turbo Boost 1.0
35 W            45 W

among the things the i3 apparently runs at faster cpu base clock speeds

other things that might be worth checking could include if
1) hyperthreading
and
2) turbo boost

is enabled on the i7 (e.g. in the bios settings)

other things to check may include the dram memory actually installed, i'd guess r@h is rather memory intensive and if so faster rams could matter

nevertheless the i7 may still run at lower speeds / performance as it is on an older 45 nm technology vs the i3 is on a 32 nm technology

this could mean that the i3 may have more advanced super scalar out-of-order pipelines since it is more recent and the feature sizes would allow putting that on the same silicon surface area

the other thing would be that the i7 being on 45nm technology would mean running at higher voltages than the i3, that would quickly push against the TDP of 45W as power is proportional to voltage squared and may cause the cpu frequency to be throttled vs the i3

btw this is 1 case which showcase an interesting fact, more *cores* do not necessary mean higher performance, recent mobile phones running on more cores at lower frequency e.g. 8 often also lose out to higher end cpus running at higher frequencies having less cores e.g. 4

i did a quick comparison here
http://ark.intel.com/compare/50178,43122

some differences become quite apparent

Certainly does. I'd check the Turbo too. Can't blame the OP for being surprised at the results.

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i did a quick comparison here
http://ark.intel.com/compare/50178,43122

some differences become quite apparent

Certainly does. I'd check the Turbo too. Can't blame the OP for being surprised at the results.

http://cpuboss.com/cpus/Intel-Core-i7-720QM-vs-Intel-Core-i3-380M

The i3-380m has (... if the above web site is correct) twice the L2 cache per core that the i7-720qm has. They both have a 1M L2 cache but the L2 on the i7 is under much more pressure and has a much higher L2 miss rate because it is shared by 8 copies of Rosetta (0.25mb per core).

Rosetta is very sensitive to cache size and memory bandwidth since they are login lots of data. It takes 1-2 clocks to access the L1, 3-6 cycles typically to access the L2 ... and on the order of 30 cycles to access the L3.

I suspect the i7 is running at its BASE 1.6ghz (due to heat) and the i3 will be running at its 2.53ghz BASE frequency. A lower frequency and higher CPI due to smaller effective L2 could easily account for the difference.

I'd bet it's heat throttling the i7... specially if it's pulling those integer and FP numbers on the benchmark. My PHONE is pulling higher numbers on the benchmark. That i7 should pull way higher numbers even at base clock.

If it's a laptop, try looking for a manual and open it up and blow the dust out. If it's a normal case computer, open the side and with a blow drier blow the dust away (outside your house preferably).

Meanwhile, try Core Temp to figure out the CPU's temperature.

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