Worth upgrading 2x4GB DDR3 RAM to 2x8G DDR3 RAM?

[FoxMulder2014]

As far as I know I can't upgrade to DDR4 ram (Motherboard is AsRock Z68 Extreme4 -

 

- Dual Channel DDR3 memory technology
- 4 x DDR3 DIMM slots
- Supports DDR3 2133(OC)/1866(OC)/1600/1333/1066 non-ECC, un-buffered memory
- Max. capacity of system memory: 32GB*

 

I reality I can only use 3 slots, because I have a huge CPU cooler to keep my i5 2500K cool

 

And using 3x8 DDR3 is bad?

2 x 16DDR3 seems overkill? (Does that even exist?)

Local store sells "2x Kingston ValueRAM 8GB DDR3 DIMM 1600 MHz (2x 1x8GB)" voor €99  


Most important will 16 GB improve the following pc worth worth a €100

 

i5 2500k

2x4GB RAM (Kingston 9905403 - 038. A00LF 1333Mhz. 1.5V (bought them in 2011)

AsRock Z68 Extreme4
RX580 8GB (yeah, it's a bottleneck, but my old broke)
2 SSD HD

1 HD

XFX PRO650W

Or should I just wait and save to get a new Mobo, case and 2x8 DDR4?

I think my GPU, SSD & power supply are still fine?

[agent_x007]

Buy another 2x4GB, unless you need more than 16GB RAM ?