|I searched for info about: Uranu II 630 W|
and all I found was a identical mention of that string on another site, in your own subject thread:
Computer reboots with no warning or error while gaming.
There is no Uranu power supply web site, or any Uranu anything computer parts related web site.
That's a bad sign.
Decent power supplies have decent web sites, and you get lots of "hits" about the model on the web, and you can find reviews about them that say they're okay.
There are lots of El-cheapo power supplies out there that are NOT good power supplies.
How much did you pay for this power supply?
Your symptoms point to a faulty power supply, or to one that has inadequate specifications for it's total +12v output, for the video chipset on the video card you're using.
GeForce GTX 275 video chipset
Minimum Recommended System Power (W) 550 W
Minimum Power Supply Requirement: 500 Watt with two 6-pin (connectors from the power supply)
What neither of them say is there is also a minimum current requirement at +12v that the power supply must meet.
The total +12v output of power supplies with the same max output wattage rating varies. El-cheapo power supply makers tend to have lower +12v output specs, or they LIE about what max current can be sustained continuously.
" My computer just randomly reboots while playing videogames, generally after 10 to 20 minutes."
Recent or fairly recent high end video games tend to place more of a load on your video chipset and your power supply +12v output than anything else.
If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should get.
In your case thats either
500 x 1.25 = 630 watts minimum
or 550 x 1.25 = 687.5 watts minimum
That's assuming the total rated wattage of your PS is NOT a LIE, and that it can put out at least the required current at +12v.
I didn't find any info about what the required minimum current at +12v is for this video chipset, but I did find this:
XFX GeForce GTX 275 XXX 896MB video card review - Power, Temperature, Noise
(Note - filtering software used on this site has replaced the two letters after eliteb with dashes - the letters that are supposed to be there are a and s. Right click on the link, copy it to somewhere, replace the dashes, then use the repaired link. )
Power consumption up to 303 watts with 3D gaming tests
Assuming the card slot can supply , say, 5A at +12v, then subtract, say, 60 watts from that - the two 6 pin connections must be able to supply, say, minimum about 240 watts, or 20 amps at +12v, and of course your other components also require some of the +12v power.
Apparently the card may have come with a Y cable that has two 6 pin PCI-E power connectors. If your power supply wiring has relatively thin wires (common with el-cheapo power supplies) , I recommend, if it has two PCI-E 6 pin connectors, that you connect both of those directly from the power supply to the card, rather than using the Y cable - the thin wiring may not be adequate to handle the required current otherwise.
From your other thread:
Check the video card temperature specifically?
Yep. It's hot (around 75ºC), but not anymore than it's supposed to be (it's made to go up to 80/85ºC) Temperatures are fine. "
When was it that temp? Right after it rebooted ?
Apparently the XFX Geforce 2xx cards tend to run hot.
You can often adjust the rpm of the fan on the card in NVidia's software. If not, apparently, it can be adjusted with other software meant for use with NVidia video chipsets. E.g. EVGA Precision 1.7.1
The faster it spins, the cooler the chipset will run at - the trade off is, the higher the rpm, the more noise the fan makes.
This page quotes a temp of less than 70 after or during 3D gaming tests:
(Note - filtering software used on this site has replaced the two letters after eliteb with dashes - the letters that are supposed to be there are a and s)
Try cranking up the fan's rpm.
Do you have case fans in the case ?
If you don't, you could probably benefit from at least one, to help dump the heat this chipset produces from the case - the best place to mount it is up high at the back.