GPU-Z Showing Core Clock drop screenshots inside. Please Help.

[Brush769]

I've been having lags and stutters in games lately and think im finally getting closer to the root (i hope). I played a 10 minute deathmatch game in CS:GO and had GPU-Z running to check what happens during the stutters. I have 3 screen shots of GPU-Z of Min/Avg/Max values of the 10 minute game i just did and it seems my core clock drops a lot and my voltage a little, could someone please look at these screenshots and tell me what they see im not very knowledgeable on this.
My Specs:
ASUS P8Z68-V Gen 3
i5 2500k running around 3.6mhz
Sapphire AMD R9 290X TRI-X OC Graphics Card 4GB, DDR5, 512 Bit
16gb ram
CX750w PSU

I've heard the PSU is terrible but im not sure if it is the PSU or the card.

http://imgur.com/a/4Myr7

 

[Brush769]

Could anyone please help im stressing out over this now is it the PSU or the Card? I tried increasing the power via CCC but it black screened i then downloaded Sapphire TRIXX and up'ed that by +50mv and it crashed during a game of CS:GO but i still had the lag spikes. Im getting Core Clock drops i believe it should be at 1040mhz while gaming but it only goes up to around 700 - 800mhz during the spikes it drops to its idle of 300mhz. Could someone please help!

 

[wa1]

Hmm, when this issue start to happen?
Is it everything is fine before?