Z68A-GD65-G E7681IMS.N00 bios does not suffer from cpu throttling

Question

Hello
I have been trying to overclock my 2500k with no good results despite having one of the best aftermarket
coolers for my CPU (Noctua NH-D14). The problem was that even with the CPU working within acceptable
temperatures, I was suffering from cpu throttling.
-Ill try to describe the cpu throttling I experienced with N10,N20 and N31 beta bios: I was trying to achieve
4.8Ghz by maintaining the stock FSB and setting the multiplier to x48. I got to boot into windows, but no
matter what I used in C1E, Speedstep, Turbo boost, C-State, C-State Limit, Short or long term wattage or core limit,
the multiplier lowered from 48x to 41x under a prime95 or linx stress test, thus leaving the system a real CPU speed
of 4.1GHz just in the moment that high CPU clock is needed!!!!!!!!.
-I have assembled cheaper Z68 mainboards form other vendors having no problems in overclocking 2500k to 4.4Ghz with much worse
CPU coolers than mine, so I decided to investigate this issue a bit.....
I realized that original N00 bios does not suffer from CPU throttling, getting easily to 4.8Ghz with 1.4v CPU, maintaining the multiplier
ad 48X for the whole AVX linx stress tests, these are the results:
-N00 bios..............................48X stable multiplier......................4.8Ghz. ................linx 119.1360 GFlops
-N10,N20 or N31b bios...........41X-48X variable multiplier.............4.1-4.8Ghz............linx 104.4250 GFlops
hope this info is useful for anyone(specially bios developers), and I havent bored you......

Answer 1

Actually, I don't need to apply any kind of load to see the throttling in any of the latest bios, I just boot into windows and open CPUZ.
With the multi set at 48 in the bios, it jumps from about 44-48. A different (lower) multi produces the same fluctuation of the multi.
Using an older bios with the G43 board completely eliminated the issue, it stays at a constant 48, or whatever other multi I choose to set in the bios.
For my Z68-GD65, the oldest bios listed on the MSI download page, which is listed as v.23.0 (7681vN0) dated 07-06-2011, is the only bios that I can use to keep a steady multiplier, and thus clock speed.
But, as I mentioned, I have EIST, Speedstep, etc. all disabled, so I will always have one clock speed, whether at idle or load.
Thus it shows immediately when just at the desktop.
I want to emphasize that I'm not trying to make a big deal about this, just having a friendly discussion about it.
I have a good workaround for now, and as I mentioned, I'm very pleased with these MSI boards. I gave the G43 to a good friend, so I can just enjoy the Z68-GD65 now.
@Bernhard: That's an interesting theory that with EIST and C-States disabled, the Primary Plane power limit and long and short duration power settings don't apply correctly, etc.
I have no clue what it means, but it all sounds very good :-D
Only thing is, why does it not happen at all with an older bios in two different boards?
Perhaps you could simply try temporarily disabling all EIST, C1E, and C-State just to see if the multi fluctuates for you when you check with CPUZ?
By the way, I'm enjoying your posts on these boards, particularly the Z68 GD65 now. You're providing a lot of very helpful information, which certainly helps me to learn to work with this excellent motherboard.
 For 4.8GHz (4809MHz in CPUZ with the 100.2 bus speed) I have the vcore at 1.420v., PLL is at 1.65v.
Quite stable there, I'm not anal with P95, but an hour or two of Prime Blend with no errors is good enough for me.
@leftyman: 1.355v. for 4.8GHz?
You've got a really good cpu there!