Very low floating point math score.

[Falcy]

Ok, i have now tried different settings in bios aswell as an optimized default.
Regardless if i run the CPU @stock, @4.2GHz or @4.6GHz, i get pretty much the same score.
It sits around 2300-2500 points.

What kind of calculation is this specific test doing? Is there any other software i can check this with?

[Falcy]

Again, would have been better to to this without O/C. I haven't really looked into it, but I suspect you shouldn't be able to get to 4.5Ghz on all cores under full load. Where as a 4.5Ghz turbo single core O/C I could believe.

I did some data mining in our database. At the moment we have 2028 examples of i5-6600K benchmarks. Of these 45 units (2%) exhibit similar behaviour of bad floating point but otherwise good CPU resutls. From these 45 "bad" units I picked 6 at random for a closer look. In each case they were overclocked units (4.7Ghz turbo in one case). The bad units were tested using various different versions of PerformanceTest that were released over the last couple of years (not just V9).

I then did the same analysis with the common i7-2600 & i7-2600k. From the ~8000 samples there was zero units that had the same issue.

My conclusion is that something goes wrong with some of these i5-6600K when they are overclocked, maybe they are susceptible to being burnt out when the voltages or temps are too high. Or maybe there is some internal throttling mechanism that we aren't aware of in this CPU.

Interesting find!
I did a default run with optimized defaults in bios and the difference in floating point math score is more or less within a margin of error, 200-300 points up/down.
I will a try a few things here.

I don't think there is any "hidden" or secret internal throttling or something like that, all other benchmarks and burn-tests works like a charm.
Aida, Prime95, Intelburn test, Cinebench, realbench, all of these are working fine.

[David (PassMark)]

Again, would have been better to to this without O/C. I haven't really looked into it, but I suspect you shouldn't be able to get to 4.5Ghz on all cores under full load. Where as a 4.5Ghz turbo single core O/C I could believe.

I did some data mining in our database. At the moment we have 2028 examples of i5-6600K benchmarks. Of these 45 units (2%) exhibit similar behaviour of bad floating point but otherwise good CPU resutls. From these 45 "bad" units I picked 6 at random for a closer look. In each case they were overclocked units (4.7Ghz turbo in one case). The bad units were tested using various different versions of PerformanceTest that were released over the last couple of years (not just V9).

I then did the same analysis with the common i7-2600 & i7-2600k. From the ~8000 samples there was zero units that had the same issue.

My conclusion is that something goes wrong with some of these i5-6600K when they are overclocked, maybe they are susceptible to being burnt out when the voltages or temps are too high. Or maybe there is some internal throttling mechanism that we aren't aware of in this CPU.

[Falcy]

If you look in task manager during the Floating point test, can you check that

1) All cores being loaded to 100% during the CPU test
2) The CPU clock speed ramps up and stays at a minimum of 3.5Ghz (it won't hit the 3.9Ghz Turbo speed as all cores should be under load).

The above will be easier to see if you pick a very long test duration from the preferences window and run the Floating point test just by itself from the Menu.
Do this without any overclocking as it keeps thing simpler.

Yes, confirmed all cores 100%. And with my 4.6GHz o/c it hits around 4.5GHz.
2398 points...

[David (PassMark)]

If you look in task manager during the Floating point test, can you check that

1) All cores being loaded to 100% during the CPU test
2) The CPU clock speed ramps up and stays at a minimum of 3.5Ghz (it won't hit the 3.9Ghz Turbo speed as all cores should be under load).

The above will be easier to see if you pick a very long test duration from the preferences window and run the Floating point test just by itself from the Menu.
Do this without any overclocking as it keeps thing simpler.

[Falcy]

If you return the CPU to normal clock speed does it fix the problem.
If you do several runs is it consistently bad?
If you look in task manager are all cores being loaded to 100% during the CPU test (this is easier to see if you pick a long test duration from the preferences window)
Are the other CPU benchmark scores OK?

I tried optimized default in bios, i get around 200-300 points lower.
As far as i can see cores are working 100%.

[David (PassMark)]

If you return the CPU to normal clock speed does it fix the problem.
If you do several runs is it consistently bad?
If you look in task manager are all cores being loaded to 100% during the CPU test (this is easier to see if you pick a long test duration from the preferences window)
Are the other CPU benchmark scores OK?

[Falcy]

Hi!
I get a very, very low score on the floating point. (~2450)
An i3 is get higher results.

I have an overclocked 6600k (45x102.25) ~4.6GHz.

No temp or throttling problem.
This cant have anything to do with my memory, because all the memory test gives me pretty high scores.

I cannot for my life understand why i get so low score?
Anyone have any idea?

Running latest version as of October 11 and latest Windows 10.