SGEMV and SGEMM performance degradation on Xeon E5-2609

Hi,

We have noticed a performance problem on a particular CPU (Xeon(R) CPU E5-2609 0 @ 2.40GHz) that we have narrowed down to a change in either SGEMV or SGEMM (or both) that occurred somewhere between MKL 11.2 Update 2 (Product build 20150120) and MKL 2018.0 Update 1 (Product build 20171007) on Windows. The slowness (relative to 11.2) still exists in MKL 2019.0 Update 4. We are using the 32-bit versions of the libraries.

Is there any known change or issue in MKL that could account for this behavior? If so, can anything be done about this? Any amount of help would be appreciated.

Thanks!

-Jake