A few people told me to check YACoin again to add to CPU Coin List since the difficulty made GPU mining much harder. Is that true?
I tried to check the HW stats on wiki but wiki is dead.
Is there an up-to-date list of GPU has rates?
I've got some insight for you:
Radeon R7 240 4GB - 1.1 KH/sec
Radeon R7 250 2GB - 0.8 KH/sec
Core i7 3610 laptop - 0.31 KH/sec
No GPU with 2GB of memory or less has shown to hit over ~1.2 KH/sec (750Ti). I don't have solid numbers on the higher end AMD cards with 4GB, but none of them can utilize all of the available shaders without lookup-gap going to the moon which really kills performance. If they hit much higher than 2.5 KH/sec I would be surprised.
so, the GPU advantage is likely less than 10x depending on what hardware you choose for GPU and CPU.