I, too, have a X5650 workstation. I’ve turned off the turbo mode because the fans were constantly changing speed, which caused a lot of noise. Also, after I had turned off the turbo, the computer’s power usage, measured at the outlet, went down from 285W to 265W. Now the fans have a even sound level, which is less distracting for me. The resource monitor shows that the CPUs run at 100% of time and at 94% of max frequency when the turbo is off.

Maybe your i7 has a much better CPU cooler, which enables the CPU to run at a higher frequency with the turbo on? For some reason my processors are running at 74 degrees Celsius, which is a lot. Before I had turned off the turbo they had run at the toaster temperature 78 degrees Celsius.

My computer has 8 fans, so the noise shouldn’t surprise me.

I also think that your 60 degrees is a good temperature and that mine 74 is too high. Perhaps I should change the CPU coolers? I bought this used Z600 workstation on Ebay and it’s probably around 4 years old, so the CPU cooler hole spacing could be outdated by now. I’ve looked inside the case and the holes for the CPU cooler seem a bit narrow compared to standard 1366 and 2011 sockets, but I may be wrong on that. I do know, however, that the Z600 has redesigned, non-standard power connectors on the motherboard and the PSU, among other things, and that also includes the fan power connectors.

The strange thing is that the exhaust air from the CPU coolers is not that hot, so I’m thinking that maybe the thermal paste needs to be reapplied. I’ve ordered a second used Z600 from Ebay with the same configurations as the first one and I’ll see how hot the CPUs are on the second. If the second computer's CPU temperatures are much lower, I’ll reapply new thermal paste on the first one. If they have the same temperature I’ll have to chose between new CPU coolers or fewer threads (I‘m crunching 24 now)?

I’m definitely going to cut down on the number of threads during the three summer months, and turn of the computers altogether when the temperature approaches 30 degrees outdoors. Running computers and AC at the same time makes no sense.

You’re right; the thinner the paste is, the better it will conduct heat. I saw a guy on Youtube use coffee filter to rub in the first layer of paste into the micro holes of the CPU lid. Only after that did he apply the second layer. He thought the small holes in the coffee filter made it an ideal material for applying thin layers of paste. And I think that could be the case. The CPU surface had a even, matt finish after the first layer.

The heat is most intensive in small areas of the CPU, as can be seen in this picture:

http://www.extremetech.com/extreme/166413-pos...-and-enthusiast-computing

So when I saw this CPU cooler ...

http://www.coolermaster.com/cooling/cpu-air-cooler/v4-gts/

... I thought that coolers made with horizontal vapor chamber technology probably must be very effective in removing heat from small hotspots.

http://www.cmuniversity.net/vapor.php?lang=en#

Problem is that not all cases have room for these large coolers. There is one that’s even larger:

http://www.coolermaster.com/cooling/cpu-air-cooler/v8-gts/

I don’t think the smaller one has reached western markets yet, but can be bought in Asia.

The hotspots put a limit on how high the frequency can go, not the average CPU temperature. What horizontal vapor technology does is to spread out the heat at the source, instead of transporting it all the way to the top of the cooler. This leads to lower temperatures at the hotspots and higher at the cooler parts of the CPU, which is how it should be.

But I need to point out that I’ve not tried any of these coolers, so I don’t know how effective they really are. Maybe the theory is good, but the build quality is bad?

I’ll try the Diamond 7 carat paste if I decide to replace the coolers or recoat the current ones.