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i am willing to buy ASUS SABERTOOTH 990FX R2.0 AMD 990FX/SB950 AM3+ motherboard and oc my 1090t(i have hyper 212 cooler)(how many ghz i can make with this motherboard?) = As Mandrake says above, there is no way to know how much more than 3.8Ghz your 1090T can go. Most really good ones on good boards with super cooling can do 4.0 to 4.1Ghz. But if you have only a fair 1090T as a few guys are discussing in another thread right now; then you might only see 4.0Ghz and 200Mhz more cpu speed is not going to fix your bottleneck problem and you have paid our money for a mobo for nothing really. IMO.
or buy cheap motherboard and buy fx 8350(this is impossible for now cuz i dont have enough money) = One a cheap motherboard and 8 core FX processor NEVER makes any sense if you wish to overclock the processor for increased gaming performance. AND you say you do not have enough money to make this purchase as a cheap motherboard and FX-8350 so if you have no money for that purchase, you certainly do not have enough money to buy a good motherboard and the FX-8350.
Now I am going to tell you an actual truth. I saw you say you might just trade down in video cards in the other thread you had about this bottleneck thing and I wondered what the heck. So did the other posters in that thread. You mean you would trade down from a high performance video card just to see percentages show up better in the usage monitors? I cannot believe that.
All that cpu bottlenecked means is that the video card maybe waiting on the cpu to hand off to the gpu. No way in heck I would trade down in video card just so the percentage of use monitors become more equal. CPU to GPU.
The situation you are in is really a head game. You bought a for sure performance video card and matched it with other subpar components. So now just because there seems a bottleneck based on use percentages you want to fix that so-called bottleneck. But you have no real money to do it. In the case of n0 money, I would just wait until I could completely upgrade the rest of my system to match my high end video card. But you cannot do that because your mind is dwelling on those cpu vs gpu percentages.
So you want us to say that the purchase of an Asus Sabertooth 990FX R2.0 which is a better board, should be purchased so you can push the 1090T about 200Mhz faster and that will remove your cpu bottleneck. NOT!
Save your money and build a system for your high end video card.