Sorry, I tried to supply as much info I could think of.

The os is Linux Mint 17.3. I make changes to the cpu settings in the bios, there is no way to do this in the os.

I use psensor for the temps and system monitor for % of cpu usage. My temps now are between 48 and 55c. I don't like to be too close to the limit.

The i5 has no hyperthreading, however I am running it with the i7. I wanted to increase the number of threads without adding a whole new system.

I thought there would be a bit of a slow down with the hyperthreading, but not this much. So this is what I can expect? I was hoping the difference in cpu speed would make up for most(?) the hyperthreading loss, however I guess the turbo was working in the i5 which would put it closer to the i7 base speed. The i5 3.4gh, turbo 3.7gh and the i7 4.0gh, turbo 4.1 - 4.4gh. I didn't think the turbo was working in the i5 for some reason which I don't remember now (what was I thinking?), so this means very little difference in the speeds between the two cpus.

Maybe I will look at a little overclocking to compensate for the longer run times, I don't think I will be able to do much with it though.

Still cheaper electrically speaking than a second system, power consumption was increased by only about 20 - 30w.

I think I will have to get a little more acquainted with the temp limits. I may see where I have a little more overhead than I originally thought.

So you run yours at 75c, how long have you done this? Have you had any problems at this temp?

Thanks for replying.

If you have lovered Vcore and you even had an error result, that means the cpu could be unstable. Lowering the voltage is the same as overclocking: it nay lead to instability.

You may have to lower the clock speed to match the voltage.

I had issues with my 4790k, excessive heat and terrible efficiency. I solved it by setting a fixed speed of 3GHz and no turbo. I lowered the voltage to the lowest stable V. Efficiency went up by 75% while power consumption was halved.

1st bold
Well, seems like the task is complete...you're doing more cores (double) & HT...so doing more jobs in the same amount of time!
It will give you the badges you deserve...so from only that, I'd sleep like a baby! ;)

2nd bold
getting 20-30W increase, for a double amount of work...or even quadruple, with HT! that's great!!!

relax...WCG is benefiting...that what you seem to return less, by making more time on single WUs...it's a WCG thing, how it valuates a donation! just relax, 'cause you're giving more by WCG standard...not maybe by RAC, not maybe by time per WU...but certainly about amount of time!
just relax...keep your computer powered on...& sleep like a baby!

The error result happened when the voltage and speed settings were default. I can't say what brought about the error, maybe it would have happened anyway.

I will be trying different configurations to see what I get this thing to do. Your suggestion will definitely be on my list.

At this time the cpu is running 4.5gh / 1.2vcore with no turbo or hyperthreading. The results look pretty good except for the power consumption, it is about 40 to 50% higher.

I don't know how accurate the "Estimate" run times are for the wus but I am completing zika wus in about half of the time estimated. The down side to this is I will probably not use this configuration due power concerns.

Thanks for your reply.