I' currently running a 9800GT Energy Efficient 512mb with a 300w PSU which came with a prebuilt computer which has a AMD Phenom II x4 QuadCore 3.0ghz + 8gigs of ram, not sure the brand of the ram sticks since it also came with the prebuilt.
Now my question is, i'm currently playing TERA Online with my 9800GT it runs fine, the heat is good doesnt get too hot, but when things start getting heavy in-game things start slowing down a lot to the point where its hard for me to do anything in-game. I havent checked my FPS while doing heavy things in game but im sure it hits the 10s if anything the single digits. My friend runs it on HIGH with no problem with his ATi HD4800 with 12gigs of ram i5 Quad. Is my GPU being bottlenecked by the low 300W PSU? Would I need a much higher watt PSU to get the full performance out of the 9800GT? If so, what would be the recommended watts for such GPU?
theres no way a 98gt will bottleneck on that cpu, yes your psu is below rating. it should be a minimum of 450w but if the card runs then the psu must be providing enough power or the system would randomly shut down, or worse not start at all.
chances are your not staying within the limitations of the gfx card, settings wise.
the 98gt is just over minimum requirements so you will get an average of 30 fps if you turn everything down to minimum... 1s you do this your fps should pick up and then use an app like fraps to measure the fps as you increase the textures first then the more system expensive effects...
my recomended settings for that game are native screen rez up to 1920/1080 low overall settings with medium textures.
You're running a 9800GT, that's your problem right there. Your friends Radeon HD 4800 is a newer more powerful card than what you have. You should look at upgrading this and your power supply. I would suggest something like a Radeon 6770/68** or NVidia GTX550/560 along with a 450-500W power supply.
Either that or lower your graphics settings, but you might not be able to reach a setting low enough to run it acceptably.
Your CPU is more than powerful enough and, unless your RAM is causing bother, I would leave them alone for now.