I9 7980xe AVX512 AIDA64 benchmark odd result at high frequency

[xma]

I am getting odd result when using AIDA64 benchmark FP32 ray trace and FP64 ray trace. when everything is auto no overclocking the result

FP32 ray-trace : 40000krays/s

FP64 ray-trace : 20000krays/s

But when overclocking and the AVX512 speed 3.9GHz

FP32 ray-trace : 20000krays/s

FP64 ray-trace : 9000krays/s

But when AVX521 3.4GHz

FP32 ray-trace : 49000krays/s

FP64 ray-trace : 27000krays/s

When the AVX512 frequency is higher than 3.4GHz the AIDA64 benchmark FP32 ray trace and FP64 ray trace result is lower than when AVX512 3.4Ghz

It looks like when increasing the AVX512 frequency more than 3.4MHz the AVX512 getting disable

Anyone notes this or its only my CPU?!

 

[LTC8K6]

Have you checked for throttling?

Are you using an AVX offset / AVX512 offset in the BIOS?

 

[LTC8K6]

For 7980XE overclocking, the typical AVX offset is 3 and AVX 512 offset is 5. That is, 300mhz and 500mhz lower clocks for the AVX/AVX512 loads.

 

[xma]

Have you checked for throttling?

Are you using an AVX offset / AVX512 offset in the BIOS?

Overclocking 4.4ghz

The offset for AVX is -3 (4.1ghz)

the AVX512 frequency after using the offset -10 for AVX512 (3.4Ghz) offset -5 AVX512 (3.9Ghz)

 

[LTC8K6]

Is it throttling? Seems like it must be throttling with AVX512 above 3.4?

These are the Silicon Lottery bins with SSE AVX and AVX512 freqs:

7980XE 4.10GHz 3.80GHz 3.60GHz 1.075V 100%
7980XE 4.20GHz 3.90GHz 3.70GHz 1.087V Top 89%
7980XE 4.30GHz 4.00GHz 3.80GHz 1.100V Top 72%
7980XE 4.40GHz 4.10GHz 3.90GHz 1.112V Top 35%
7980XE 4.50GHz 4.20GHz 4.00GHz 1.125V Top 8%
7980XE 4.60GHz 4.30GHz 4.10GHz 1.137V Top 2%

 

[xma]

Is it throttling? Seems like it must be throttling with AVX512 above 3.4?

no it is not throttling

when I run the FPU stress in AIDA64 which test the AVX 512 the frequency is 3.9 doesn't goes lower

but the temperature at 3.9Ghz is lower than when its at 3.4ghz

 

[LTC8K6]

Strange...

Perhaps not all cores are running at 3.9?
But all cores are running at stock and at 3.4 overclock?

 

[xma]

Strange...

Perhaps not all cores are running at 3.9?
But all cores are running at stock and at 3.4 overclock?

hwinfo show all the cores running at 3.9ghz

 

[LTC8K6]

hwinfo show all the cores running at 3.9ghz

During the benchmark?

Seems strange. Not sure where to go from here.

 

[Zucker2k]

It's throttling, no doubt. Check with Intel XTU:

 

[xma]

I found that it needs more vccin voltage 1.95v