Questions about new gaming Build

Hi im John im new at the forums and im resuing my old machine to make a gaming rig

APPROXIMATE PURCHASE DATE: Until january 10
BUDGET RANGE: 530€ but i don´t want to change the config´too much just to see if all fits together well

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT:
composing in fruity loops , working the photoshop , word ,etc.. , surfing the net , heavy gaming


PARTS NOT REQUIRED:
Drive- Write master x22 drive
HDD- Hitachi Sata II 7200 RPM Sata II
Case- Sucky case with one single 80 mm fan and an air exit( i don´t know the model)
PREFERRED WEBSITE(S) FOR PARTS: Im from Portugal so i shop at pixmania

PARTS USED:
CPU- AMD Phenom II 965 BE 3.4 GHZ 140 €
Rams- OCZ Pc memory Obsidian Ultra-Low Voltage 2 x 2 GB DDR3-1600 PC3-12800 90€
GPU - Ati radeon Hd 4890 140 €
PSU- OCZ StealthXStream 600 W 66 €
Motherboard- ASUS M4A785TD-V EVO - Socket AM3 - Chipset 785G - ATX 80 €

OVERCLOCKING: Only 200~400 mhz in each memory
I can´t crossfire with this mobo so no...

MONITOR RESOLUTION: 1280x1024


QUESTIONS:
1- Is the system compatible?
2- Will the Psu hold up with such a demanding system , will i have performance problems of some sort?
3- Do i need to worry about the temps of this sytem?Since my case will do a lousy joob keeping it cool ... How well do the stock collers of the CPU and GPU( of course) hold up?

ADDTIONAL NOTES:
The memories are configured for intel processor so that won´t be a smart choice maybe , i have to find ones fitting to my cpu..



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links for hardware

Motherboard -
http://www.asus.com/product.aspx?P_ID=QHbvGVB1mXmmD8qQ&...
PSU-
http://www.ocztechnology.com/products/power_management/...
GPU-
http://ati.amd.com/products/radeonhd4800/overview-4890....
Rams
http://www.ocztechnology.com/products/memory/ocz_ddr3_p...
CPU
http://benchmarkreviews.com/index.php?option=com_conten...