Should I Lower The GPU?

GPUboss is not really a very good comparison website and generally don't recommend basing any decisions off of it around here.

Same goes for CPUboss.

Here it is not so bad due to the cards being basically the same, but for cross-platform (AMD vs Nvidia) it is about worthless.

In reality the 280 is still a very good card and will still run all your games at a mix of high and max most of the time.
 
I never said anything about Anandtech man. But for the cards they do have they FAR exceed GPUboss is accuracy and quality. Generally we don't recommend GPUboss and CPUboss.

One other way to look at these cards is what they actually are. The 280x is a 7970 and the 280 is a 7950 BOOST. 280 and 280x are just the new names for the R9 series, but they are basically the same cards.

http://anandtech.com/bench/product/1033?vs=1032 here is a comparison of the cards. The 280 is only a bit worse, and generally will not be too noticeable. The difference will only been seen in an instance where the 280x will get 60fps and the 280 will only get 55. 55 looks alot different than being locked at 60. The difference between 65 and 80 doesn't matter as you will only be playing at 60fps. 60 is the number you care about. EXAMPLE: If the 280x gets 66fps average in a game at ultra then you can comfortable play it at ultra, but if the 280 only gets 55fps average, you will definitely find yourself lowering the settings to play locked at 60fps rather than bouncing around in the low to mid 50s and seeing spikes and dips.