Why is amd fx 8150 slower than 15

IPC.

Instructions per clock. The i5 gets mor done per clock cycle, per core.

(Although the 8150 does perform better than the i5 in some tasks where the extra cores are used)

There's a lot to that question, but the basics are that more than 4 cores don't mean anything for gaming, the 8150 doesn't perform like a true 8 core CPU should (8 integer cores, but only 4 Execution units), and the Bulldozer architecture is much slower than Intel's Sandy or Ivy Bridge (IPC, like. Z1NONLY said).

You also can't compare speeds between them because the architectures are so different (and of course, they're from different manufacturers).

Main overall point: Don't be fooled by AMD's "more cores is best for EVERYTHING" argument and their claim that the 8150 is a true 8 core CPU. Very little main stream use for more than 4 cores, anyway (just in video encoding, mostly).

Games don't make use of more than 2 or 3 cores so you could have a 16 core monster and it won't make a difference untill the games use that many cores. So it comes down to what those two or three cores do when compared against each other and the archatecture and instruction sets are what makes the difference as ZINONLY said and once it's pattened another manufacturer can't copy it or use it without permission from the pattend holder and Intel isn't goung to allow its competitor to use it. So it's always a race to be the first.
If you have some process that requires 8 cores then the 8150 is the cpu for you or you can get a six core Intel cpu with hyperthreading and have 12 threaded cores.

http://www.tomshardware.com/reviews/gaming-cpu-review-o...

This is a chart of the rating of cpus and what are the best down to the worse and you can see where the FX 8150 comes in and the Phenom cpu is ahead of the 8150.

Agree with all the above folks, the main reason is INTEL offered much better instruction per second.

Intel is the first microprocessor developer that is why intel has much more experience than amd.

Best answer selected by fajardokier.