|I said in Response 4 ...|
"...the Geforce 8400GS video must be on a card in a slot.
I look on the web finds that....
- your video card would have at least a heat sink, or a fan and heat sink
- a minimum of a 350watt power supply is recommended, 18 amps or more for +12v. "
".....i saw i have EZ Cool ATX-300 JSP 300W... and under
+12VDC i think the max. output was 18A..."
A = Amps; 18A = the max. amperage rating for +12v
The amperage rating at +12v equals the minimum for the video chipset , but the total (D.C. output) wattage rating does not.
Your power supply is running at 100% of it's max capacity, or nearly so, all the time, when the Geforce 8400GS video card is installed.
According to info I've read, from several sources, the max (output) capacity of a computer power supply is an intermittent rating - NOT a continuous or sustained rating - the power supply is not supposed to run at it's max capacity all the time .
When the power supply is running at that rating all the time, or nearly so, it's likely the power supply will eventually be damaged.
"....so my problems are just in games."
Games tend to make the video card's video chipset use the most current, which draws the most current from the power supply.
"should I buy a new graphic card or what?"
If your video is NOT fine when you first boot the computer after the computer has had a chance to cool to room temp, and for a while after that, if you're sure the video card is all the way down in it's slot (you could also try removing the card, when the AC power to the case has been removed of course, wiping off the contacts on the bottom or the card, installing it again) then your video card must be damaged, and you must replace it.
If your video is fine when you first boot the computer after the computer has had a chance to cool to room temp, and for a while after that, and you only have video problems after the computer has fully warmed up....
Your problems will probably be cured by you getting a power supply that has a higher (output) capacity.
At least 350 watts - more wouldn't hurt, and when you're a gamer, it's recommended you multiply that by 1.25 to determine the minimum capacity = 437.5 watts minimum - the closest common standard wattage would probably be 450.
If you want to be able to use a video card in the future that draws more current, get at least a 600 watt one, or higher.
In any case, you probably need to get a power supply with more capacity. If you get a card with different video chipset, the capacity of the PS must be at least the minimum recommended for a system with the video chipset that's on the card, and better still, when you're a gamer, it should be at least 1.25 X that minimum.
You can usually replace it with any decent standard sized standard ATX PS with the same capacity or greater.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo PS.
See response 3 in this: