Andreas1416 :
Hi
I'am building a gaming PC and my GPU is Sapphire radeon r9 280x toxic.
What is the best CPU for this GPU?
I would advise modifying your question to the following:
"What CPU is best for the software I want to run (X, X, X) with the following performance goals (X FPS, etc)?"
There is no such thing as a "best CPU for a GPU" or a "best GPU for a CPU." They handle totally separate workloads which are not heavily influenced by each-other.
Match the CPU to the compute workload.
Match the GPU to the render workload.
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We often get the same "bad" question in reverse: "
What GPU is best for my CPU?"
Again, that question should really be modified to:
"What GPU is best for the software I want to run at the following visual quality settings (resolution etc) and performance (FPS)?"
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If your performance goals with the R9 280X are to get 30FPS in modern games at 1440P with high-ultra settings, then the best value CPU for you is something like an i3, or 860K, or FX-6300, as any of these ~$100 CPU's will run most games at 30FPS just fine.
If your performance goals withthe R9 280X are to get 120FPS in modern games at 720P ultra, then the best value CPU for you is going to be an i5-4690K or i7-4790K overclocked as high as you can get it.
If your plans are somewhere in the middle like most people, you'll probably be pretty happy with an i5-4590 or similar for ~$200, or if you want a little more compute headroom, opt for the E3-1231V3 for ~$240.