Bree,

Some of the performance is impacted by the BIOS version on the CPU:

Code:
BIOS
Version 2902 2016/04/155.43 MBytes

Z97-K BIOS 2902
Improve system stability
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Version 2901 2016/03/315.43 MBytes

Z97-K BIOS 2901
Improve system stability
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Version 2801 2016/01/095.37 MBytes

Z97-K BIOS 2801
Improve system stability.
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Version 2701 2015/11/185.36 MBytes

Z97-K BIOS 2701
Improve system stability.
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Version 2604 2015/05/285.37 MBytes

Z97-K BIOS 2604.
Support new CPUs. Please refer to our website at: http://support.asus.com/cpusupport/cpusupport.aspx?SLanguage=en-us
*Before using the 5th Gen Intel Core processors, we suggest that you use USB BIOS Flashback or download ”BIOS updater for 5th Gen Intel Core Processors”to update the BIOS.
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Version 2603 2015/04/225.36 MBytes

Z97-K BIOS 2603
Improve system stability.
*Support NVMe
*Before using the 5th Gen Intel Core processors, we suggest that you use USB BIOS Flashback or download ”BIOS updater for 5th Gen Intel Core Processors”to update the BIOS.
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Version 2602 2015/03/165.34 MBytes

Z97-K BIOS 2602
Support ASUS USB 3.1 PCIE add-on card
*Before using the 5th Gen Intel Core processors, we suggest that you use USB BIOS Flashback or download ”BIOS updater for 5th Gen Intel Core Processors”to update the BIOS.
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Version 2503 2015/03/135.34 MBytes

Z97-K BIOS 2503
Enhance the compatibility with some CPU Fans
*Before using the 5th Gen Intel Core processors, we suggest that you use USB BIOS Flashback or download ”BIOS updater for 5th Gen Intel Core Processors”to update the BIOS.
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Version 2502 2015/02/155.33 MBytes

Z97-K BIOS 2502
1. Implement 5th-Generation Intel Core Processors code
*Full support of the new CPU requires necessary driver updates.
2.Enhance the compatibility with some CPU Fans
*Before using the 5th Gen Intel Core processors, we suggest that you use USB BIOS