Optimal Ddr3 On Old Asus Motherboard

Hello everybody
I have a relatively old Asus P8Z77-V LX.
In it`s manual stated that it supports the following memory variants (could copy from the pdf, so here`s a link to the img) :
https://ibb.co/h7soGQ
(1066 Mhz -1600) and up to 2400 OC

1. So if I buy DDR3 which is 2400 from the manufacturer, will it run fine ? Does it depend on changing settings in BIOS and overclocking ?

Now I don`t understand what`s my current memory speed, CPU-Z states that it`s 800 Mhz, But I think it should be around 1600 Mhz (bought in 2012). Please take a look on the img & txt :
https://ibb.co/cBxAVk
Here`s a link to my cpu-z report (text) :
http://textuploader.com/drcg7
I think I have this model :
http://www.eteknix.com/geil-enhance-corsa-ddr3-1600mhz-8gb-memory-kit-review/

2. I`ve heard it`s recommended not to use 4GB with 8GB RAM, but is it just if used in pair ?
What if I add 2x8 to my existing 2x4 ?
And should they be of the same speed ?
Or should I only use 4x8 ?
The cpu fan is blocking one of the slots, so I might use only 3 of the 4 I have !!!
Or maybe there are less protruding DDRs ?
OR can I cut the metal heat dissipators to shape (cut in the middle so they fit around the fan) ?
https://ibb.co/dbMFwQ

3. Other things I need to know about it ?

Thanks for any help

 

Here's a list of compatible memory: http://dlcdnet.asus.com/pub/ASUS/mb/LGA1155/P8Z77-V_LE/Z77_memory_report.pdf

DDR = Double Data Rate 800 x 2 = 1600

I have 4+8GB in my laptop and it works.

It should work. If it doesn't, you'll still be up to 16GB, from only 8GB.

All your RAM will normally work at the speed of the slowest clockrated piece. Example: You put DDR2400 with your original DDR1600, it will run at DDR1600 speed. Overclocking may affect that, but I don't mess around in that department. You'll need to wait for someone with more experience to opine.

I personally would add the 2x8GB and see what happens.

Personally, I wouldn't go hacking up those pieces. I would measure that space under the fan then check into low profile RAM for fit.

Get canned air and blow out that dust.

 

If you visit just about any memory maker's website, they typically have a memory wizard of some sort where you either download a little scanner, or you plug in the information then the wizard will tell you what your motherboard supports and offer suggestions. The Crucial Memory Advisor is an example. You don't have to buy their RAM, but you should buy RAM with the same specs. But note if buy directly from Crucial, they guarantee compatibility.

 

Agreed.

Hacking into heat spreaders tends to void warranties. Measure, or look at the detailed fan specs on the manufacturer website,then buy RAM that will fit underneath.