Running 4 sticks of ram (2 sets of 2 x 4GB) in XMP?

[norse85]

I have been running 1 set of 2 x 4GB DDR3 1600MHz since I build this pc years ago.

LINK

I decided to upgrade to 16GB so I could keep up with more demanding games (Star Citizen Alpha).
So I purchased another set of 2 x 4GB DDR3 1600MHz (except the Low Profile version so that it could fit under my CPU heatsink) as from what I understood there would be no problems upgrading your ram in this way.

LINK

I ran this benchmark before and after the upgrade http://www.userbenchmark.com/Software and both times I was warned that my ram is running well below expected averages for its type, and I should set up an XMP profile via BIOS. I went into BIOS and noticed that my ram is, and I guess always has been, running at 1333MHz instead of 1600MHz. From what I understand Intel force ram to run at lower frequencies as a safety measure so the pc will always boot?

In CPU-Z the different ram sets are running at slightly different latencies.
Is this because slot 2 + 4 are running in Dual channel mode, while 1 and 3 are running in single? Or is it because the sets are different and they will never run at the same speeds?

https://ibb.co/cjzpLp
https://ibb.co/izzpLp

My question is can I set my XMP profile to run at 1600HMz without damaging my ram or CPU? Or should I just play it safe and run these 2 seemingly mismatching sets at 1333MHz for the life of the PC?

Thanks!


EDIT: Oh I should probably post more specs hey...
Mainboard: Gigabyte Z77X-UD3H
CPU: Intel i5 3570K @ 3.4GHz Ivy Bridge
GPU: GeForce GTX 970 4GB (but that's not relevant)

 

[Calvin7]

Memory is guaranteed to perform at rated specifications for the memory in the form it is sold. XMP settings are also for a single kit.

How to run BIOS settings on memory that has never been tested together is up to you and your compatibility testing with no guarantees. Running memory at slower speeds and with relaxed timings and higher voltages may be needed to get extra memory to work together.