£300 PC upgrade

[harvey_bear]

Nearly a year ago i built my first PC and am looking to upgrade it. I have £300 to spend but i'm not sure what to spend it on. Something that will make a noticeable difference in everyday use or in gaming.
Thanks
My current system:
Processor: i5 4670K cooled by Hyper 212
Motherboard: Gigabyte Z87-D3HP
Graphics: EVGA GTX 770
Memory: Corsair Vengance 8gb
Storage: Western Digital caviar green 1TB / Crucial M4 64gb

 

[Eduello]

£300 won't get you much of an upgrade, [strike]unless you SLI your GPU[/strike]. What PSU are you using?

EDIT: Never mind, your motherboard doesn't support SLI.

 

[Au_equus]

is the ssd cached to the HD? SLI the 770 or get a larger SSD

 

[Eduello]

I recommend saving a bit more and getting one of these (If your PSU can handle it): http://uk.pcpartpicker.com/part/gigabyte-video-card-gvr929xoc4gd

 

[harvey_bear]

is the ssd cached to the HD? SLI the 770 or get a larger SSD

I'm currently using my SSD just as a boot drive and the mechanical for storing everything else like games.

 

[dasulman]

buy a larger power supply - 750-800W +
buy an SLI z97 mobo
buy a larger SSD
that fits £300
or you could buy better peripherals? keyboard, mouse, headphones / sound system
may be mod your case? improve cooling? may be get a new case?
there's a fair bit you can do